https://gsuiteupdates.googleblog.com/2020/03/less-secure-app...
Since May 1st, using IMAP to access a G Suite account stopped working, though, with a message:
> IMAP command 'AUTHENTICATE PLAIN <authdata>' returned an error: NO [AUTHENTICATIONFAILED] Invalid credentials (Failure)
I know the credentials are good because they work in the browser. Maybe an automated process somewhere kicked in?