Solved Modulus SIP trunk incoming calls fail

[InfinityGrape]

Using a self-hosted cloud PBX, 18.0 (Build 415) version. I have a CYTA sip trunk working normally
While I am adding a second trunk, the modulus trunk with the template incoming calls fail. Outbound work normally.
DID is in the correct format, tried with + with *, also without.
A short Wireshark pcap showed after the INVITE 407 Error Proxy Authentication required
BUT then in the next Request the error becomes 403 Invalid credentials
I am confused here. I tried to disable call source identification on both trunks but nothing works. Call immediately drops.
I also requested another password from modulus which it did not work.

Also tried to specify my PBX public IP via header - that did not work as well.

When I talk with their support they are telling me that they get continuous 407 and 403 and I am entering something wrong but I cannot find it.

I could use some help, thank you guys!

 

[phonemaster]

Using a self-hosted cloud PBX, 18.0 (Build 415) version. I have a CYTA sip trunk working normally
While I am adding a second trunk, the modulus trunk with the template incoming calls fail. Outbound work normally.
DID is in the correct format, tried with + with *, also without.
A short Wireshark pcap showed after the INVITE 407 Error Proxy Authentication required
BUT then in the next Request the error becomes 403 Invalid credentials
I am confused here. I tried to disable call source identification on both trunks but nothing works. Call immediately drops.
I also requested another password from modulus which it did not work.

Also tried to specify my PBX public IP via header - that did not work as well.

When I talk with their support they are telling me that they get continuous 407 and 403 and I am entering something wrong but I cannot find it.

I could use some help, thank you guys!

There was an update for modulus template in update 5, so go to Settings-Updates page of 3CX and check if you have an update there.
If yes, download it. If not, this means that it's already downloaded.
Go to Trunks page, delete your modulus trunk and add it again.

Most probably, something changed on the modulus side and template update is fixing it.

 

[YiannisH_3CX]

Hi @InfinityGrape

There was a change in the Modulus template which would cause the issue you are describing. To solve it please update to the latest version V18.0.5.418 and download the newest Modulus template from the downloads section. If its not available then it most probably auto downloaded after the update so don't worry .
Delete your existing trunk and recreate it using the latest template.
Add your numbers/DIDs in the E164 number format (eg +30210XXXXXXXXX)

Let me know if that solves your issue

 

[InfinityGrape]

Hi Guys,

Thank you very much for your reply.
I was really happy to see that there was available update for the modulus SIP trunk and I said great this is it. I also did the version update but after re-adding the trunk I get the exact same behavior.

Do I need to enable the Convert Inbound caller ID to e164 number format in the Caller ID tab?
or to disable the call source identification?
I tried both anyway but no luck.
Any other tips?

Again thank you very much for the prompt response.

 

[YiannisH_3CX]

Did you add your numbers in the correct format using "+"?
Can you send me a screenshot of your inbound parameters to check?

Also are you still seeing the same behavior? Do the calls come in and 3CX is sending 407 proxy authorization required?

 

[InfinityGrape]

Hi Yiannis,

Yes I am using the correct format with "+".
Exact same behaviour, yes (see below)



Also Screenshot of Inbound Parameters (default)

 

[lotsosK_modulus]

Hello,

Please try to configure the following settings for every SIP Trunk and let us know if it's working as expected.



One more thing that you have to do, is to inform modulus customer support in order to configure your SIP Trunks to be compatible with the 3CX platform (that matters for the +e164 format).

In the next days, modulus will announce one more update. In this update will be supporting the rinstance feature that will resolve finally similar issues.

If you still have issues, try to reach the customer support!

 

[YiannisH_3CX]

If you used the new template and recreated the trunk you should have the following setting in your inbound parameters:


Not sure how you ended up with the ones you have but try these ones and let us know.

What @lotsosK_modulus suggested will also work but if you have multiple trunks on the same machine it might cause routing issues.

 

[InfinityGrape]

Hi Guys,

After hours of troubleshooting, talking to their support with no solution at the time, I suddenly tried to call the number in the afternoon and to my surprise the call went through normally.

I am guessing there has been an update on the SIP trunk which solved the issue.

Thank you all for your help!