fyi
The first time you sent an encrypted memo it will ask you to enter ether the owner key or active key.
Ignore that and enter your Private Memo key
press ok
it will ask for owner or active again so enter one or the other.
The next time you send an encrypted memo it should go through immediately.

When I tried to enter my active key on the first request I got stuck in a loop and needed to send the msg un-encrypted to escape the loop.