Microsoft SBA can not connect with the MS teams client

[Amauri_Crovador]

I have a configuration involving multiple SBA's that was operational for a few weeks. However, I recently encountered an issue where calls to the SBA ceased functioning after disconnecting the internet connection from both Teams and SBA clients. Despite ensuring that certificates and licenses are correct, the problem persists.

In the SBA log, when a call originates from the PSTN, the following entries are visible:

• INVITE): Move from Initial -> Notifying state"|""
• Sending call notification to: "internal ID" "|""
• No active registration for: "internal ID" "|""
• SIP/2.0 480 Temporarily Unavailable

However, when the call is initiated from the Teams client towards the PSTN, there is no corresponding entry in the SBA log.

(Note: Teams clients are properly associated with the SBA.)

Do you have any suggestions for debugging this issue?
Thanks
Amauri

[#2]

@Amauri_Crovador I had similar issue, this did lead me in lot of different directions when i first started troubleshooting on this issue.  First thing to check is.

#To make sure the Branch FQDN and Branch Appliance policy in teams PowerShell is set correctly with lower case.

#Check in Teams SBA logs with the object ID of the account which has the policy assigned.

# Check teams client logs to make sure the survivability mode = True and there will be Keepalive Post message like below, it should show success. IF not check to make sure 8443 is not blocked, because the teams client uses that to communicate to SBA. You can try to connect the teams client in the same network as sba and sbc.

HTTP request DM SurvivabilityService POST : POST "https://sbaserver.com:8443/api/v1/keepalive"

If all above is okay, then the next step is to check the firewall and make sure the azure stack ip's are allowed, i know the list is huge, but thats what MS wants you to. Or you can simply check in the firewall rules and see the deny's and add only them to allow.

[#3]

Hi @ManojBaskaran27 

I'm encountering similar issues, but while my Teams soft clients are functioning as expected, the Teams phones are not. I've tested with Yealink MP54 and Cisco IP phones, but unfortunately, I haven't had any success. Both the phones and Teams clients operate perfectly when there is internet connectivity. However, when the internet connection is disrupted, the phones cease to function while the Teams clients continue to work in survivability mode.

I've confirmed that my SBA FQDN are correctly configured and same as the SBA policy, but it is in uppercase. This is evident as the Teams client on Windows PC operates smoothly, in contrast to the Teams phones. Do you have any suggestions for resolving this issue?

Regards,

Shalid

[#4]

Ports 3443, 4444 and 8443 are used by Microsoft SBA Server to communicate with the Teams client and should be allowed on the firewall. I guess its allowed in your case since your Teams client on your laptop is able to register to the SBA server. Definitely fix the upper case issue, i know Microsoft had that issue in the early stages of SBA, but now they might have addressed it. But i would get it changed for Branch FQDN/Certificate SAN name/Server Name & SBA policy to all in Lower Case just to sure. Also you can run wireshark captures from the phone, different phone models have different ways to do them, pls look in to some articles for the same.

Last thing to check would be in the firewall to see if any denys /reset's for the phones IP and add them in f/w.