Call from MITEL 3300 SIP to 2nd PBX, Call drops after 44seconds

[Toodyt]

Hello!
We have a 3300 connected through a SIP Trunk to a 2nd PBX.
When a call is made from the MITEL the call drops after 44seconds.
The Mitel goes Quiet. The 2nd PBX phone gives Dial tone.
This is true for Analog and VOIP.
Call is good from 2nd PBX to MITEL.

Session  Timer  on both are 90 sec .
Is there a timer that may cause this in the SIP PEER.

[pmhaynes]

If you increase the timer from 90 to 180 does the call then drop after 90 seconds?

[Toodyt]

My apologies for not getting back to this.
The problem was due to Firewalls and multiple 3300's.
The RTP flow was not directed properly because it needed a proxy.

Thak you

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