Forum Discussion
REASON Q.850;cause 18 text Call Controller timed out while waiting for acknowledgement.
Incoming calls to Microsoft teams get disconnected automatically after 20 seconds. You can make a call from outside, teams phone rings, answer the call, 2 way communication is there but still teams c...
I have this problem and it is solved as the following.
- make sure the contact header in the 200 OK sent to the SIP provider is your SBC the correct IP, so the SIP provider will reply with ACK to the IP in the contact
Note: if you are using NAT or accessing a public SIP provider, so you need to NAT the IP from the internal to the external IP, then you have 2 options
- if you are using UDP or TCP: then the contact IP should be the internal IP and the Firewall will be able to do the NAT and change the contact IP to the external.
- If you are using TLS: then the contact IP should be the external IP as the Firewall will not be able to do the NAT.
hope this will solve your problem