I had an issue with VMware Workspace ONE UEM Tunnel. Users report that they are occasionally unable to connect to an application through the VMware Tunnel.

The VMware UAG Tunnel Edge Service showed green sign indicating it was up.

The UEM Tunnel Test Connection showed once in a while “No information to display”

And also once a while Error Console to AWCM

After researching the UAG Debug log, I saw a number of errors related to DNS.
The issue was due to a faulty NIC of the host running one of the DNS servers.
After fixing the NIC everything worked properly again.