Google has been mucking up Less Secure Apps settings. Please make sure you still have Less Secure Apps enabled for that account. If you do, then you will need to create an application password (especially if you’re using 2FA).
I’m working with Google to approve the project I’ll be using to release the oAuth version of RBE so that these things don’t happen in the future.
Let me know if the steps above resolve the issue for you.