[MlMt] MM keeps demanding passwords

[Randall Gellens]

I migrated from my long-time High Sierra laptop to a new one (currently 
running Big Sur as I had some problems with Monterey). Mailmate moved 
over mostly fine, but when the laptop has been idle for a while, or just 
when MM feels like it, it pops up a dialog demanding the password for 
various accounts, claiming the password isn't in the keychain, which it 
is. I open Keychain Utility, copy the password to the clipboard, paste 
it into the box, and MM is happy for a while. Very annoying.

I upgraded yesterday to 5852 but no difference.

--Randall