None of the agents are registering to a Task Server. Errors on the agent logs shows messages like these:
Error code: HTTP error occured (0x80042D21)
Error note: Authentication failed, response to server challenge denied, check credentials are correct, error: The logon attempt failed (0x8009030C)
Error code: HTTP status 401: The request requires user authentication (0x8FA10191)
Error note: Empty response content received
"Custom Agent Connectivity Credential defined for this profile" was set to use wrong credentials.
In Console Check: