TeamViewer is showing offline - with unattended access for the software vendor company



We use an application installed on a windows 2012 server. We have the software support with the application vendor and the software vendor company has installed TeamViewer unattended access. 

When escalation support calls to their helpdesk, they directly log into the server using the unattended access and get the issue sorted.

Recently they are saying that when they try to remote into the application server using the TeamViewer unattended access - TeamViewer is showing offline.

They say that TeamViewer is not starting, there is something preventing unattended access on the server-side.


I checked the TeamViewer services on the server, and it is in the running state, and the startup is set up to automatic.


Not sure what else I need to check so that they can have unattended access without the TeamViewer going offline.

This is causing issues and the company gives this reason and are not able to attend the support call.

The TeamViewer version running on the server is 15.26.4

Is there anything I need to check?

Please help and suggestions to resolve this issue would be great.

 Thanks in advance.