SQL Server 2014 AOAG Issue Have a current AOAG setup with 1 database.  Trying to add a 2nd database.  It's in FULL recovery mode and I performed a FULL backup.  When I try to add the database, it says I need a FULL backup and the check box is "grayed" out so I cannot select it.

I have not found anything on Google with information on this so hoping someone who is a "guru" on AOAG can point me in the correct direction.
Please see this which consists of all the things you need to do before you add a DB to existing AOAG :

https://msdn.microsoft.com/en-us/library/ff878487.aspx