Skype Connect SIP Trunk

[FelixTECH]

Hello!

I have added a Skype Connect SIP Trunk and corresponding outbound rules. When I dial a number I always get that error:
Call or Registration to ***@(Ln.10000@Skype Connect) has failed. *** replied: 403 Forbidden; from IP:***:5060
The SIP Trunk in 3CX is green and logged in.
In Skype Manager I can see the calls I attempted to make with correct international phone number format.
Microsoft itself provides no support for Skype at all.

 

[leejor]

If the IP you *'d out, is the IP for Skype, then they don't like something, obviously. Given 3CX shows registered, your 3CX settings may all be correct, but not necessarily.

The issue could be one of the following....

The number format you are sending is incorrect

The Caller ID you are attempting to send is not accepted, incorrect format

The destination number cannot be called (no call credit, or the number is a high rate number, and must be unblocked through Skype)

Can you receive incoming calls?

You may consider looking through the Skype community.

https://support.skype.com/en/faq/FA10549/what-is-skype-connect-and-how-does-it-work

https://answers.microsoft.com/en-us...&threadType=All&isFilterExpanded=false&page=1

 

[Rhys Haskell]

Hello!

I have added a Skype Connect SIP Trunk and corresponding outbound rules. When I dial a number I always get that error:
Call or Registration to ***@(Ln.10000@Skype Connect) has failed. *** replied: 403 Forbidden; from IP:***:5060
The SIP Trunk in 3CX is green and logged in.
In Skype Manager I can see the calls I attempted to make with correct international phone number format.
Microsoft itself provides no support for Skype at all.

Is the trunk IP authentication or username/password authentication?

Have you followed the instructions here:
https://www.3cx.com/blog/docs/configure-3cx-with-skype-connect/

 

[FelixTECH]

Yes, the trunk is user/pass authenticated.
Thanks for the documentation. I have made sure that everything is configured in that way.

I have now added call credit to that SIP profile in Skype. Didn't know I have to do that. Now I can do outbound calls.

But I can't do any inbound calls. I have a Skype number assigned to the SIP profile and that number is in the SIP trunk in 3CX entered and a DID rule exists. But when I call that number I get the message "The number you have dialed is not in service."

 

[Rhys Haskell]

Yes, the trunk is user/pass authenticated.
Thanks for the documentation. I have made sure that everything is configured in that way.

I have now added call credit to that SIP profile in Skype. Didn't know I have to do that. Now I can do outbound calls.

But I can't do any inbound calls. I have a Skype number assigned to the SIP profile and that number is in the SIP trunk in 3CX entered and a DID rule exists. But when I call that number I get the message "The number you have dialed is not in service."

If you run a packet capture on 3CX do you see an INVITE from Skype?

 

[FelixTECH]

If you run a packet capture on 3CX do you see an INVITE from Skype?

No, I cannot see any SIP related packets on tcpdump. Not even when I do a (working) outbound call.
The 3CX firewall checker is green for the SIP server.

 

[leejor]

That fact you are reaching, what sounds to be a provider recording, and you've confirmed that you are not even seeing an incoming Invite, you might want to check your Skype account settings, to see if inbound calls have been properly set up. There may be some options that you have missed.

 

[cobaltit]

This thread is a perfect example of why 3CX supported trunks are recommended. Unless your time isn't worth anything your time + unsupported provider cost is going to be more expensive then what a supported provider costs.

 

[FelixTECH]

This thread is a perfect example of why 3CX supported trunks are recommended. Unless your time isn't worth anything your time + unsupported provider cost is going to be more expensive then what a supported provider costs.

Skype Connect is under the "worldwide" SIP trunks available and according to the Skype website supported and certified: https://www.skype.com/en/features/skype-connect/

 

[cobaltit]

I don't see them listed here:

https://www.3cx.com/partners/sip-trunks/worldwide/

And it's great that Skype says it's certified. So they should be the ones helping you no? Or perhaps their website is just out of date. Skype should work with 3CX (I've set it up in the past) but again, if you don't know how to configure it or troubleshoot it then you are better off sticking with one of the folks on the list. It used to be listed on the supported provider's page but I don't see it anymore. But generally supported providers (like us) provide test trunks to 3CX so they can do interop testing as they release updates and adjust the templates as needed. There's also links to the support guides for configuring inbound/outbound rules, etc so things just work.

Another way to put it would be this. Let's say you get it working and then it stops one day (thing the worst day possible because that's how Murphy's law works). Have you tried calling Skype support? Can you call Skype support? Skype was great back in the day for when you wanted people to be able to reach your PBX from the Skype client. Haven't used it much since the. There's better providers out there from a support and ease of use perspective.

But anyways, should you want to continue down this path, if you can't see any SIP packets when doing a wireshark capture for incoming calls then it's not a 3CX issue. Until it hits 3CX it's not a 3CX issue. I want to say you had to do some associating of the numbers to the Skype Connect trunk so I'd look into that first. Once you have calls actually reaching 3CX you may able to figure it out on your own or at least have a relevant log entry here to post for help. But there's too many possible reasons why it's not hitting your PBX. Firewall checker being green and the ability to call out points to a Skype trunk configuration issue.

 

[FelixTECH]

I have chosen Skype because when I open the create SIP trunk dialog I can find it there and in the past I had never problems with Skype. By past I mean the time before Microsoft owned Skype.

I wasn't able to find any support contact details for Skype. Seems they don't even offer support.

As Skype got this crappy I have decided to change the provider anyways but I would really like to know why it doesn't work. I looked into the firewall stats and when I try an inbound call I cannot even see traffic trying to reach by 3CX server. The issue is clearly on the Skype side.

 

[cobaltit]

So as I wrote before, I believe it was a 2 part process where you had to point the DID/TN in Skype specifically to a endpoint/SIP trunk via the Skype Manager. But this is my recollection from way back when so I have no idea if that's still accurate. But it would seem that Skype doesn't know to route calls to your number to 3CX.

 

[FelixTECH]

So as I wrote before, I believe it was a 2 part process where you had to point the DID/TN in Skype specifically to a endpoint/SIP trunk via the Skype Manager. But this is my recollection from way back when so I have no idea if that's still accurate. But it would seem that Skype doesn't know to route calls to your number to 3CX.

That is true. When you enable incomming calls you have to assign one or more phone number(s) to that SIP profile. My number shows up as enabled for incomming calls but it doesn't work. And Skype doesn't provide any support and has absolutely no way of contacting them.

 

[Rhys Haskell]

That is true. When you enable incomming calls you have to assign one or more phone number(s) to that SIP profile. My number shows up as enabled for incomming calls but it doesn't work. And Skype doesn't provide any support and has absolutely no way of contacting them.

Does skype use TLS, is a similar way that teams does?

 

[N_G]

Its best to forget about Skype connect. I did not even know it still existed. Use a standard supported SIP trunk and you will get better results. That certification was done before microsoft even bought it

 

[FelixTECH]

Does skype use TLS, is a similar way that teams does?

There is no technical documentation. I have no idea.

 

[FelixTECH]

Its best to forget about Skype connect. I did not even know it still existed. Use a standard supported SIP trunk and you will get better results. That certification was done before microsoft even bought it

That explains why it worked before Microsoft bought it

 

[N_G]

@FelixTECH hahaha, exactly!!!! After that it was game over for Skype