I am using android studio 3.5.3 on Ubuntu Budgie 19.10, whenever I log into github from the android studio, it works but only for the current session, when I close and reopen android studio, it says Missing access token
and asks for login.
Earlier I was using elementary OS Juno and everything was fine, I did not need to login again and again.
As said by fartem, you need to set "Save Passwords" option
from "Do not save, forget passwords after restart"
to "Native keychain" or "KeePass"
in File> Settings> Appearance & Behavior > System Settings > Passwords