Hello @Anonymous !
Welcome to Microsoft QnA!
Please provide more info :
Which SBC are you trying to implement ? Ribbon ? Audiocodes ?
A major issue that most users forget is the Baltimore Certificate Installation
You can download the certificates over here.
The more details you provide the better help you can get !
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!
Regards