When trying to launch an application session using Kerberos authentication, the following error appears at the bottom-right in the Workspace: No valid credentials provided (Mechanism level: Server not found in Kerberos database (7)).
In the log files (awingu-application-gateway.service.log), a similar error can be seen:
2023-02-16 08:15:21.408209+00:00 somehost awingu-application-gateway.service[java:1575481]: cs-id: 64266773-ef29-4e6c-a6c4-8a27798e51f7 message: GSSException: No valid credentials provided (Mechanism level: Server not found in Kerberos database (7))
There is no PTR record for the RD Session Host on the global DNS server(s) defined in Awingu.
Check which global DNS servers are used (System Settings > Global > DNS).
On those DNS servers, make sure there is a PTR record for each RD Session Host and individual RD Connection Broker.
Do mind that this is a limitation in case a FQDN for an RD Connection Broker cluster was specified, which is not a recommended configuration at this point. See Configure a RD Connection Broker in Awingu .