Intermittent 403 Forbidden from SIP provider

[MikkelAnd]

Hi,

We are using an unsupported SIP provider with a number of fully updated v16 3CX installs and intermittently we are unable to complete any outbound calls.

When this occurs we need to restart the SIP service on the afflicted 3CX server. We tried disable/enable the trunk, but that isn't enough to rectify the problem.

Call or Registration to Destination-Phone-Number@(Ln.10000@SIPTRUNK (Generic SIP Trunk)) has failed. IP.of.SIP.Provider replied: 403 Forbidden; from IP:IP.of.SIP.Provider:5060

This past weekend our ISP/SIP provider had a serious issue which pretty much blocked all traffic. This resulted in all SIP trunks going offline with the following error

Registration at SIPTRUNK (Generic SIP Trunk) has failed. Destination (sip:IP.of.SIP.Provider:5060;transport=TCP;lr) is not reachable, DNS error resolving FQDN, or service is not available.

Entirely understandable.

After the ISP fixed the problem - which impacted all traffic, not just SIP - we had 4 seperate 3CX installs with 403 Forbidden errors when attempting outbound calls which could only be solved by restarting the SIP service. Inbound calls were not affected.

I believe the error is on the side of the service provider, but if anyone has experienced anything similar I would love to hear about it to better.

Mikkel

 

[leejor]

403 Forbidden can happen when any number of conditions arise, that the provider does not like.

This can be things such as sending an unacceptable caller ID, insufficient credit, or attempting to call a number that is at a higher rate than a limit you have set. So, until you ask your provider, what the issue, in your case, is, it is all going to be speculation.

The fact that it worked after a restart means it may be something to do with registration, but, again, have them check what is going on, while it is having an issue. Since they were experiencing other issues, you issues may be related.

 

[MikkelAnd]

Hi,
That's pretty much was I was afraid of - unfortunately the service provider is not what I would call forthcoming when it comes to assistence in troubleshooting.

/mikkel