Workplaces not able to switch between "This Computer" and "Desk phone" (Sometimes)

[Menniss]

IP Office Server edition running R11.1.3.2.0 Build 6, Workplaces is 3.37.0.156

The IPO is in the cloud with managed WAN links to most of the customers sites, some connect via the Internet.

Everything about Workplaces (including Presence) is fine with the exception of one site. The site with the issue is connected via the internet. Look to me like a firewall/networking issue.

Hoping someone may have seen and can point me in the right direction.

Details.

User has an issue when in the office and cannot switch between the "This Computer" and "Desk phone" in workplaces Desk phone is not an option. This only happens when is this particular office which is connected via the internet.
It works in these tested scenarios
1/ Any other public internet connection
2/ Another office of the same customer using the internet (network should be setup the same)
3. / Another office of the customer on the manged WAN

We will be going to the IT people to see if they can see any differences in the network's setup.

It looks like it uses port 443 for this "Avaya Workplace uses MTCTI Protocol over WebSocket."

Has anyone seen this?

 

[derfloh]

I agree that it sounds like a firewall issue. If not maybe asymmetric routing or a NAT that breaks things.