reportserver will not join basic availabiltiy group
Found the answer, but still don't understand WHY it works.  if anyone can share any insights it would be appreciated. 

Issue with adding a database to an availability group

So, using the answer from the post above did NOT work when doing the join only mode.  I was able to get it to work by doing the below:


fully recovery the DB on node1.  do NOTHING on node2 with the DB so I can use automatic seeding.
Go through automatic seeding, and see that the DB did NOT show up on node2
Run the below queries on node2.  they failed for me for error 41106

ALTER AVAILABILITY GROUP [agname] JOIN; 
GO 
ALTER AVAILABILITY GROUP [agname] GRANT CREATE ANY DATABASE; 
GO 
Remove the DB from the AG on Node1, then add it back in with the GUI.


After this the DB showed up on node2 and is in the AG properly. I would love to understand WHY this works if anyone has info.