u/Hellrazed

r/SamsungSupport Query

Query Identification: 01098172

Title: [Galaxy S24 Ultra – Incoming VoLTE calls receive 180 Ringing then CANCEL cause=600 "Busy everywhere"]

Description:

I have an intermittent incoming-call failure on an Australian Galaxy S24 Ultra on Optus. It affects multiple callers and appears strongly location-dependent, but mobile data continues working and the handset remains registered for Optus VoLTE/IMS.

I have captured the failures in multiple Samsung Developer Options bug reports.

The failed calls consistently show this IMS/SIP sequence:

IN: INVITE

Handset enters RINGING

OUT: SIP/2.0 180 Ringing

Approximately 0.8–1.0 seconds later:

IN: CANCEL Reason: SIP;cause=600;text="Busy everywhere"

OUT: 200 OK to CANCEL

OUT: 487 Request Terminated to the original INVITE

Only AFTER receiving the CANCEL does Android/Samsung record:

ImsReasonInfo: CODE_REMOTE_CALL_DECLINE (1404)

Samsung code: 3009 / INCOMING_REJECTED

Therefore the handset appears to successfully receive the incoming VoLTE INVITE and return 180 Ringing before subsequently receiving a remote/network-side CANCEL.

The problem has been reproduced with at least three different originating phone numbers.

Samsung/Android call filtering in the captured failures shows DND false, number NOT BLOCKED, direct-to-voicemail Allow, and no identified local automatic rejection.

I specifically investigated Samsung Call & Text on Other Devices/CMC because CMC activity appeared in the logs.

Calls + Texts ON: failed. Calls OFF / Texts ON: failed. Calls + Texts OFF: failed.

When Call on Other Devices was disabled, the CMC voice-fork attempt disappeared from the logs, but the primary incoming call still failed with the identical:

INVITE → 180 Ringing → inbound CANCEL cause=600 "Busy everywhere" → 487 Request Terminated

Therefore CMC voice forking does not appear to be required for the failure.

During controlled testing I captured successful and failed incoming calls while moving between locations. The fault can transition from working to repeatedly failing within 1 km of home.

I subsequently captured repeated failures while returning home, followed by a successful incoming call without rebooting, toggling airplane mode, or manually resetting the network between the failures and success.

The successful call was confirmed in the Samsung logs as VoLTE, not Wi-Fi Calling/ePDG.

Optus has recorded the SIP sequence above, including three affected originating phone numbers, and has escalated the issue to its back-office team.

Samsung has also been sent a Samsung Members Error Report with system logs.

My main technical question is:

What could cause/trigger the inbound SIP CANCEL with cause=600 "Busy everywhere" approximately one second after the handset has already accepted the terminating INVITE and returned 180 Ringing?

I am particularly interested in whether this could originate from Samsung's IMS/modem behaviour, another forked terminating branch, or the carrier IMS network.

Things I have tried:

• Restarted phone multiple times.
• Confirmed phone/software fully updated.
• Deleted and reprovisioned Optus eSIM twice.
• Checked/reset mobile network and call settings.
• Tested 5G/4G Auto and 4G preferred – no change.
• Tested Wi-Fi Calling on and off – no change.
• Checked call forwarding – none configured.
• Checked call barring – none enabled.
• Checked FDN – disabled.
• Checked DND, blocked numbers, direct-to-voicemail and Samsung call filtering – no local rejection identified.
• Tested with car Bluetooth connected and disconnected – failures with both.
• Tested Call & Text on Other Devices with Calls + Texts ON, Calls OFF/Text ON, and both OFF – failures in all configurations.
• Troubleshot separately with Samsung support.
• Completed troubleshooting with Optus technical support.
• Tested incoming calls from at least three different phone numbers.
• Conducted controlled mobility testing with repeated incoming test calls.
• Generated 7 Samsung Developer Options bug reports around successful and failed calls.
• Confirmed handset remains Optus VoLTE/IMS registered during captured failures.
• Confirmed successful comparison call was VoLTE rather than Wi-Fi Calling/ePDG.
• Submitted Samsung Members Error Report with system logs and relevant SIP findings.
• Optus has escalated the fault to back office.

Have not yet tried sacrificing a goat while leaving it on charge for an hour.

Device Name: [Samsung Galaxy S24 Ultra]

Device Model Number: [SM-S928B]

Best regards, u/Hellrazed

Optus/S24 Ultra: incoming VoLTE call gets 180 Ringing, then network sends CANCEL cause=600 “Busy everywhere” ~1 sec later — strongly location-dependent

I'm chasing a very weird intermittent incoming-call failure on an Australian Samsung Galaxy S24 Ultra on Optus, and after seven Samsung developer bug reports and some slightly ridiculous controlled testing, I have actual IMS/SIP evidence rather than just “sometimes my phone doesn't ring.”

I'm particularly interested in opinions from anyone who works with IMS/VoLTE/mobile core/Samsung IMS, because Optus has now escalated this to back office and Samsung has an error report.

What happens during a failed call

The failure is extremely consistent in the Samsung logs:

"IN: INVITE"

Handset accepts the terminating call and enters "RINGING"

"OUT: SIP/2.0 180 Ringing"

Then ~0.8–1.0 sec later:

"IN: CANCEL"

"Reason: SIP;cause=600;text="Busy everywhere""

Handset responds:

"OUT: 200 OK" to CANCEL

"OUT: 487 Request Terminated" to the original INVITE

Only after receiving the CANCEL, Android/Samsung records:

"ImsReasonInfo: CODE_REMOTE_CALL_DECLINE (1404)"

Samsung code "3009 / INCOMING_REJECTED"

So unless I'm badly misreading this, the S24 isn't locally declining the call and then generating the 600. It has already returned "180 Ringing" and subsequently receives the CANCEL containing ""Busy everywhere"".

This has been reproduced with at least three different originating phone numbers.

Things already tested/excluded

During failures:

- handset remains registered for Optus VoLTE/IMS;

- voice/data remain in service;

- incoming INVITE successfully reaches the handset;

- Samsung/Android call screening shows DND false, number NOT BLOCKED and direct-to-voicemail Allow;

- no obvious call forwarding/diversion is configured;

- failures occur with and without Bluetooth call audio;

- changing 4G/5G hasn't fixed it;

- Wi-Fi Calling on/off hasn't fixed it;

- Optus eSIM has been deleted/reprovisioned twice.

I also specifically tested Samsung Call & Text on Other Devices / CMC.

With COOD enabled, the logs show CMC attempting to fork the call.

I then disabled Call on Other Devices only. The CMC voice-fork attempt disappeared from the logs — but the primary call still did:

"INVITE → 180 Ringing → inbound CANCEL "Busy everywhere" → 487"

I then disabled both Call and Text on Other Devices and reproduced it twice more with the same SIP sequence.

So CMC voice forking does not appear to be necessary for the failure.

The really weird part: location

Calls are reliable at home but have repeatedly failed elsewhere, including at work.

Today I deliberately drove away from home while someone repeatedly called me.

The first call, shortly after leaving home Wi-Fi, worked normally as VoLTE.

Less than a minute later the failures began.

They then remained reproducible while driving and while stationary around my street and local area.

On the return trip we repeatedly called the phone while creeping through the final streets approaching my house. The final ~11 failed calls occurred over basically entering the street before mine and then reaching my driveway.

Same sequence every time:

"INVITE → 180 → ~1 sec → CANCEL "Busy everywhere""

Then, once I was physically in the garage, the next incoming call worked.

There was no reboot, airplane-mode cycle or network reset during that failure → success sequence.

The successful call in the garage was also confirmed in the Samsung log as VoLTE, not Wi-Fi Calling/ePDG.

The phone had already associated with home Wi-Fi before that successful call, but voice was still carried over cellular IMS.

Interestingly, earlier testing also showed the same visible LTE PCI carrying both a successful and failed incoming call, so I don't think this can simply be reduced to “one bad PCI/tower.”

Haiku for Engineering

Optus sends INVITE.

Samsung replies “180 Ringing.”

Optus sends CANCEL.

Okay, technically the syllable count is fucked.

What I'm trying to understand

What could cause the terminating IMS side to send:

"CANCEL"

"Reason: SIP;cause=600;text="Busy everywhere""

after the UE has already returned 180 Ringing, particularly in a way that appears strongly associated with mobility/location?

My suspicion is now somewhere around Optus terminating-call routing / subscriber IMS state / another forked terminating branch / mobility-dependent IMS state, although I'm deliberately not assuming this proves an Optus fault. A Samsung modem/IMS interaction that causes something upstream to make that decision is still possible.

What I'd really like to know from someone familiar with IMS is:

Who would ordinarily originate a cause-600 “Busy Everywhere” CANCEL in this situation, and what should Optus be looking for in their S-CSCF/SBC/application-server trace to identify the branch or event that caused it?

Optus frontline support has recorded the exact SIP sequence plus three affected originating numbers and has now escalated it to back office. Samsung also has a fresh error report.

At this stage I'm mostly trying to understand what the other side of this SIP conversation is likely doing.

I'm trying to work out whether this is a Samsung issue, a Kenwood issue, or something else.

For years I've used a Samsung phone with a Kenwood DDX6 over Bluetooth without any problems. The head unit was installed nearly 10 years ago and the firmware hasn't changed for around 6 years. Nothing on the car has changed.

About a month ago (around the same time as a major One UI update), Bluetooth audio suddenly became much quieter.

Symptoms:

Both media and phone calls are affected.

The Bluetooth connection itself is solid—no dropouts or reconnects.

Turning the Kenwood volume up doesn't restore normal volume. It just produces very quiet, distorted audio.

The phone also seems to override attempts to increase Bluetooth call volume during calls, even with volume limits disabled.

I'm using:

Samsung Galaxy S24 Ultra

Spotify for music

AutoZen instead of Android Auto (the DDX6 is too old for AA)

Both apps have worked flawlessly with this setup for years. No settings have been changed in Spotify, AutoZen or the head unit.

So far I've:

Cleared the Phone app cache.

Checked Bluetooth settings.

Confirmed Bluetooth connection quality is stable.

Confirmed nothing has changed on the head unit.

Planning to wipe the Android cache partition next.

Before I start chasing firmware updates on the Kenwood, I wanted to ask:

Has anyone seen this after a recent Samsung update?

Is there a known Bluetooth audio-level issue with older Kenwood units?

Would you expect this to be a phone problem, or is there something on the DDX6 I should be checking first?

My suspicion is that the phone is now outputting a lower Bluetooth audio level after a recent update. However, before I assume it's entirely a Samsung issue, I'd like to rule out anything specific to older Kenwood Bluetooth implementations or DDX6 settings. I'm just trying to rule everything out before I start replacing hardware or chasing the wrong problem.

I'm trying to work out whether this is a Samsung issue, a Kenwood issue, or something else.

For years I've used a Samsung phone with a Kenwood DDX6 over Bluetooth without any problems. The head unit was installed nearly 10 years ago and the firmware hasn't changed for around 6 years. Nothing on the car has changed.

About a month ago (around the same time as a major One UI update), Bluetooth audio suddenly became much quieter.

Symptoms:

Both media and phone calls are affected.

The Bluetooth connection itself is solid—no dropouts or reconnects.

Turning the Kenwood volume up doesn't restore normal volume. It just produces very quiet, distorted audio.

The phone also seems to override attempts to increase Bluetooth call volume during calls, even with volume limits disabled.

I'm using:

Samsung Galaxy S24 Ultra

Spotify for music

AutoZen instead of Android Auto (the DDX6 is too old for AA)

Both apps have worked flawlessly with this setup for years. No settings have been changed in Spotify, AutoZen or the head unit.

So far I've:

Cleared the Phone app cache.

Checked Bluetooth settings.

Confirmed Bluetooth connection quality is stable.

Confirmed nothing has changed on the head unit.

Planning to wipe the Android cache partition next.

Before I start chasing firmware updates on the Kenwood, I wanted to ask:

Has anyone seen this after a recent Samsung update?

Is there a known Bluetooth audio-level issue with older Kenwood units?

Would you expect this to be a phone problem, or is there something on the DDX6 I should be checking first?

My suspicion is that the phone is now outputting a lower Bluetooth audio level after a recent update. However, before I assume it's entirely a Samsung issue, I'd like to rule out anything specific to older Kenwood Bluetooth implementations or DDX6 settings. I'm just trying to rule everything out before I start replacing hardware or chasing the wrong problem.

I've got an S24 Ultra and I'm trying to work out whether a recent One UI update has broken something.

About a month ago (the major update was 5th July) two problems appeared at roughly the same time.

**1. Incoming calls are randomly being declined**

The phone buzzes once, I briefly see the incoming call banner, then the call is immediately marked as declined.

If I'm driving, Bluetooth pauses my music for a second, then resumes because the call has already been rejected.

It has happened to multiple legitimate callers including:

- my dad

- my mum

- my daughter

- my surgeon

- a nursing home mobile

I've watched it happen, so it isn't the callers hanging up. I can immediately ring them back.

I've already checked:

- Numbers are not blocked

- Call Screening is off

- Direct Voicemail is off

- Modes & Routines aren't active

- Bixby disabled

- Spam protection only blocks high-risk scams

- Cleared the Phone app cache

- No voicemail is configured with my carrier

**2. Bluetooth audio output is now extremely quiet**

At almost exactly the same time, Bluetooth audio became very quiet in my car.

The head unit is a Kenwood DDX6. It's been installed for nearly 10 years, and the firmware hasn't changed for about 6 years. Nothing in the car has changed.

Both phone calls and media are affected.

Turning the volume up on either the phone or the Kenwood doesn't restore the previous volume. Instead, I just get quiet, distorted audio, as though the phone is sending a much lower-level signal than it used to.

I primarily use Spotify for media playback and AutoZen instead of Android Auto (head unit is too old for AA). Both have worked flawlessly with this setup for years. I haven't changed any settings in either app, and the Bluetooth connection remains stable. The only issue is that both music and phone calls are now being output at a much lower level than before, with increasing the volume only resulting in quiet distortion rather than restoring normal volume. During calls, the phone repeatedly lowers the Bluetooth call volume after I increase it. I can turn it back up, but it reduces itself again even with volume limits disabled.

The Bluetooth connection itself is stable. It doesn't drop out or reconnect; it's just suddenly much quieter than it has been for years.

What I've tried:

- Checked all Phone settings

- Cleared Phone app cache

- Confirmed nothing is blocked

- Confirmed Call Screening is off

- Confirmed Direct Voicemail is off

- Confirmed Modes & Routines aren't triggering

- Bixby disabled (never been enabled)

Versions

- Phone: Samsung Galaxy S24 Ultra

- One UI: 8.5

- Android: 16

- Phone app: 16.2.00.81

- Spotify: 9.1.72.1891

- AutoZen: 8.0.10

- Kenwood DDX6 firmware: TBC

I'm planning to wipe the cache partition next, but before I go down the factory reset route...

Has anyone else had both random declined incoming calls and very low Bluetooth audio output after a recent One UI update?

I'd be interested to know if this is a known issue or if anyone has found a fix.