SX20 SSL connection rejected

[alina.hsia]

The endpoint SX20 show a 'SSL connection rejected' message under SIP Proxy 1 column. 

We try to follow Solved: This looks interesting George - Cisco Community  to try to resolve issue, but still happen.

This endpoint registration on CUCM. 

Thanks.

[Wayne DeNardi]

If you're using self-signed certificates, try turning TlsVerify Off in your SIP settings on the endpoint.

Alternately, make sure that all your certificates are current and signed by an authorised Certificate Authority.

[alina.hsia]

Thank you for your reply. May I know is the software version related to this issue? Because the software version is TC 7.3.18 bd50440.

CUCM System version: 12.5.1.11900-146

[Wayne DeNardi]

No, the issues isn't related to the software version - the software version you have can be successfully SIP registered.

However, in saying that, TC7.3.18 is a very old software release, and due to security fixes and feature updates, you should consider upgrading it.  Depending on your controller (if you are using a Touch10, or a TRC6 remote) it'd be recommended that you update to the latest CE9.15.13.0 release.  If you are using an older controller (a Touch8 or a TRC5 remote), you should either upgrade to a newer controller (and then to CE9), or if staying with the older equipment, at least update to the latest TC7 release (TC7.3.21 from March 2020).