Unattended robot remains disconnected after upgrade

My unattended robot has stopped working after auto-upgrade to 2021.4.2. This is the Studio Community edition running against Cloud Orchestrator with only one seat. Connection type is Service URL and not Machine Key. Status in the assistant shows “Connected, Licensed.” I am not using personal workspace. There is only one machine associated with the tenant. 1 unattended runtime is allocated to that machine.

Unattended robot was created using the unattended robot option for my user. Prior to the Studio upgrade, the robot could be successfully triggered by orchestrator. Looking at the robot status in Orchestrator, the User sessions correctly show Status as Available and license type as Attended (RPA Developer Pro). Under unattended sessions, the status shows Disconnected and last heartbeat as “a day ago” which is approximately when the system upgraded. The version also differs from the Studio version with 21.4.0 instead of 21.4.2.

As near as I can guess, the robot can no longer ping Orchestrator with the heartbeat after the upgrade. I just can’t figure out how to fix it.

I should also note that after the upgrade, I had to log out and then back in through the assistant to get it to connect.