Firefox (linux): Webdialer doesn't actually dial, calls just immediately drop

[[c14g] Cyber Security]

I use Voxtelesys + 3CX hosted start-up.

It SOMETIMES let me make outbound calls but it's usually 25% (success) /75% (failure)

Issue:

• When placing an outbound call, the dialer doesn't connect or dial.
  • You can sometimes hear it attempt but it immediately closes the dialer
• If I place a call to my personal cell phone it goes STRAIGHT to voicemail and never rings my cell.

Attempts to resolve:

• Tried 2 different Chromium Based browsers instead of my standard firefox.
• Tried Private mode in Firefox
• Tried dialing out of my cell phone app (Android) and got the same result
• No updates on the O/S (Debian x64 Stable on GNOME3)
• Tried restarting workstation
• Looked for firewall blockage (non found, as it's all hostted in 3CX + Voxtelesys VOIP)
  • We do use DPISSL (deep packet inspection via Watchguard Firewalls) but I am unable to find ALL the needed domains for 3CX dialing outbound (not sure if 3CX even does certificate pinning)
    • To be safe I added my instance domain into the DPISSL bypass, same result.
  • if this was the problem it wouldn't work 25% of the time, it would simply NEVER work.

Thank you,
Scott [c14g]

 

[[c14g] Cyber Security]

Support was able to determine the problem.

I resolved this by going to 3CX Panel > Admin > Users > *Select Caller* > removed Outbound Caller ID because there was a typo.