Francis Upton any plans to close out this issue? it's a blocker for us. Only way we can seem to get it to work is to keep saving the credentials manually (which forces a refresh). However it means we can't use it for automation.
This is an issue with us as well. Almost verbatim the same symptoms as described above. I have confirmed with AWS support this is indeed a session timeout. The plugin does not re-auth and refresh the session. Maybe a session refresh interval as a configuration option or something along those lines.