Call transfer terminated after few seconds.

[Sove]

Hi,

I have configured a call flow apps to transfer calls; the call is transfered correctly but it is terminated after 4 seconds.

The 3CX is connected to a Audiocodes Mediant that manage the trunk to the provider.

I found that the Provider, after the 200 OK, it sends an INVITE and 3cx replay with 100 Trying. After that the provider send other 3 INVITE and then the call terminate.
I temporaly resolved it blocking the INVITE from the Mediant.

There is no issue if in the SIP trunk I transfer the call to an extension.

Do you have any suggestion about this issue?

I attach the call flow obtained from the Mediant.

 

[JohnS_3CX]

You can try to disable re-invites on your trunk.

 

[Sove]

Hi,
in the trunk, inside 3cx, the support re-invite it is already disabled.

 

[JohnS_3CX]

Hi Sove,

If the log is what I think it is, then the provider is having an issue with your Mediant, and the Mediant is sending bye to the provider, and then its also sending BYE to 3CX.

So I don't think this is a 3CX issue at all, but probably something that you need to check with your provider and your SBC manufacturer

 

[Sove]

Thanks you.
But I have this issue only when I use call flow apps.
If the call go to a queue, a ring group or a single extension it works without issues...

 

[NickD_3CX]

What does this Call Flow app do exactly? Just trying to get a better understanding.

 

[Sove]

1 -The call arrive to 3CX.
2 -The Callflow keep the number and query the CRM to return the extension that can answer to that customer
3 -After that the call is transfered to that extension.
4 -If the number is not found, 3cx transfer the call to the operator.

At the point 3, the call is correctly trasfered to the extension, but after 4 secs ends.

If I use queues, ring group or the call transfer if the extension is in "away status", the call keeps up until it goes to voicemail.

 

[Sove]

If I use the CF app with another operator there are no issues...but I would to know why 3cx not reply to the INVITE.
ah..the first call of day works...

Anyway i resolved (workaround) disabling the "remote re-invite" in the Mediand.

 

[NickD_3CX]

I have been trying to replicate this but without luck so far.
I am thinking that this may be some race condition in the specific timing where your provider sends the re-INVITE after the call has been answered.

If you have the time for a small test, could you try and slightly increase the "Delay" value of the transfer and check if the same happens?

Default it is 500ms, increasing it to 1500ms should do the trick.

 

[Sove]

Ok, thanks.
I'll try.

 

[Sove]

Wow ... it seems to work.
I have tried with some calls and they are transferred successfully with no problems. I will monitor in the next days

Thanks a lot