We’re having an INTERMITTENT issue when callers are placed on hold. After our agent picks back up after hold, there is no longer any audio (or occasionally one way audio). We have absolutely no other problems with our system, and no audio issues except after a hold. (This does NOT happen with every hold. Maybe only 1 in 5 or 1 in 10 holds are affected.)
We are using Sangoma s705 endpoints. We are us using TLS, SRTP. I’ve been working with a fully licensed/certified sangoma consultant on this, and they are about at their wits end trying to figure out what the problem is.
We’ve worked with our local router, making sure the TCP state timeouts are correct, no firewall issues, etc. We’ve checked and re-checked the extension settings, Asterisk SIP settings, etc.
The only thing I haven’t done is tried a different endpoint - to rule out a firmware bug?? I ordered a couple Yealinks and will test them this week to see if they are also affected.
Can anyone suggest anything else I should be looking at in this regard? When viewing logs for affected phone calls, the only obvious abnormality I see is some of this sort of thing:
res_srtp.c: SRTP unprotect failed on SSRC 660505557 because of authentication failure 160
I see a LOT of this as well:
“res_srtp.c: SRTCP unprotect failed on SSRC 298925605 because of unable to perform desired validation”.
Any suggestions would be much appreciated!!