u/Equivalent_Joke_7181

We are a public school having issues connecting with parents after our transfer from PRI, to SIP. We have had this problem since pretty much the cutover Dec. 29th 2025. We get waves of secretaries telling us, ring twice, dead air. Most of our calls that are not being connected at T-Mobile users. I have added all of our lines to Hiya, TNS, First Orion, in hopes that it would fix the issue. It worked for Verizon, but we believe that T-Mobile (First Orion) has a algorithm setup when our calls start to invade their lines. Here is a report of just May 1st 2026.

Hour	Attempts	Completed	Failures	Success Rate	ALOC
0 AM	76	70	6	92.11%	0.18
1 AM	37	36	1	97.30%	0.18
2 AM	57	57	0	100.00%	0.18
3 AM	13	13	0	100.00%	0.19
4 AM	13	13	0	100.00%	0.19
5 AM	72	72	0	100.00%	0.19
6 AM	70	68	2	97.14%	0.30
7 AM	59	50	9	84.75%	0.67
8 AM	172	162	10	94.19%	1.42
9 AM	218	202	16	92.66%	1.14
10 AM	231	204	27	88.31%	1.55
11 AM	187	169	18	90.37%	1.46
12 PM	195	175	20	89.74%	1.79
1 PM	199	188	11	94.47%	2.03
2 PM	238	209	29	87.82%	2.02
3 PM	153	139	14	90.85%	2.13
4 PM	102	92	10	90.20%	1.47
5 PM	29	29	0	100.00%	0.93
6 PM	21	21	0	100.00%	0.37
7 PM	33	33	0	100.00%	0.38
8 PM	26	26	0	100.00%	0.29
9 PM	25	25	0	100.00%	0.18
10 PM	13	13	0	100.00%	0.17
11 PM	21	21	0	100.00%	0.23

Have anyone seen this kind of drop off in the most busiest hours of our day 7 AM to 4 PM? Who do you think I should blame, the cellular or our SIP Provider.

Thanks.