Well... It is working now. I guess I was trying too many "fixes" and missed the case where my base test (CN=IP certificate and CN=non-IP certificate) with [Peer Certification Validation] = "off" would pass and continued looking elsewhere... Thank you again Tata for the help, much appreciated.

Thank you for the reply Tata. I currently have [Peer Certification Validation] = "off". My other TLS related configuration on the same page are as follows: [TLS-handling] = "on" [Queue Size] = "50" [Maximum Active Connections] = "0" which is unlimited [Enable TLS 1.0 or older] = "disable" [Request ...

1. Brekeke Product Name and Version: Brekeke SIP Server, Version 3.9.1.3 2. Java version: 1.8.0_201 3. OS type and the version: Windows 10 Pro, 64bit OS 4. UA (phone), gateway or other hardware/software involved: - 5. Your problem: First of all if this problem is not related to Brekeke, I am sorry ...