3CX and outbound calls

I have succesfully setup PBXww with a flynumber (Guatemala) and connected to a SIP Account. Using the address and credentials, the SIP Trunk on my 3CX PBX and on PBXww show up as registered succesfully. I am also receiving inbound calls with no problem.

When calling outbound, I get the following error:
Registration failed for Guatemala Flynumber SIP Trunk
Cause: Cause: 401 Unauthorized/REGISTER from

Seems like something my PBX sends to FlyNumber is causing the registration not to work.

STUN is disabled, sRTP is disabled and I’m dialing out with this format 50225079797.
UDP Ports 10000-32767 and TCP 5060 are open on the firewall for the following IPs:

What am I missing? Thanks for the help.

From reading around, I suspect it might have something to with this setting in 3CX but have no clue.

Hi @esori

Thanks for the update and I also suspect its something in the settings, if you can send us the full pcap and a screenshot of the settings we will look at this

Thanks and standing by

Just figured out the problem from a tip on an email from your support department: “username” must be the same as “fromuser”

In 3CX, that is fixed in the SIP Outbound parameters like this:

Voila! Working now.

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Super and glad to hear this worked

Thank you for posting the solution and standing by if you need anything at all