I factory reset my router because of a suspected security issue. I've changed the WiFi password but it will not allow me to change the admin password saying "Unexpected Error" (I've tried several times) It gives a link to a technical page which is dead and there's an error code -

http://linksys.com/jnap/core/SetAdminPassword2 : {"adminPassword":"my new password was here","passwordHint":""} -- connection: close content-language: en content-length: 81 content-type: application/json; charset=utf-8 date: Wed, 01 Jul 2026 12:29:48 GMT server: lighttpd/1.4.39 status: 200 OK x-frame-options: SAMEORIGIN

I regularly change my password usually without problem.

Can anyone help please, Thanks.

EDIT - Also a code at the beginning - 2298

EDIT 2 - In case anyone ever comes to this sub as it seems dead really, I solved my issue eventually. I have no idea why but this router will not accept either "{" or "}" in Admin. passwords despite ticking the "special character" requirement when you type it in. Weird I know but there you go.

EDIT 3 -

For what it's worth AI says -

"Linksys firmware restricts special characters like { and } in admin passwords primarily due to legacy input validation and security sanitization protocols. 

Technical Reasons for Restriction

1. Input Sanitization and Security Filters

Older Linksys firmware versions employ strict string sanitization to prevent code injection attacks (such as Cross-Site Scripting or command injection).  Characters like curly braces are often flagged as potential script delimiters. When entered, the firmware may silently strip, convert, or "scramble" these characters (a phenomenon known as mojibake), causing a mismatch between the stored hash and your login attempt." 

Of course this is all irrelevant once you know. Could have saved me some time if I already knew.