Same problem on windows 11 client. After update of NetBak PC Agent to ver. 1.2.0 and Hyper Data Protector to ver. 2.2.0, backup is not stopped. Obtain same error and no more control from NetBak. Check if the HDP protector console on QNAP still working for already setted backup work, but cannot control from NetBak PC Agent, so cannot make change or new backup for new clients.
Hope Qnap release a solution for this…