Can't just set HADR back to ON if the replica is disconnected.
If you have no experience in AOAG's I wouldn't have put that technology in place for something as critical as HADR.
Does that DB in question belong to the AG VM02?
It looks like either it wasn't fully created on the replicas properly as it is missing from one replica, or that replica has had some of the metadata removed.
Backup the DB in question, trash the AG and set it up again from scratch.