It's an on-prem CVAD integration scenario with Citrix Workspace Service.
In the first logon attempt, user authentication and resource enumeration take nearly 2 minutes after inputting user name and password in the Cloud Workspace.
However, the consequent logon attempts are a bit faster compared to the first attempt.
Unreachable sites are added to Workspace which caused timeout error during enumeration.
In splunk log of Workspace, we can see below error: