Appears this has been a consistent issue off and on throughout the past few years.
I have one PC that this occurs on (just starting using this PC)... and it does it for BOTH FF and Chrome.
Uninstall, reinstall doesn't help. It works for the new sign-in, but once logged out, and logging back in, it fails. It's like the DB is getting corrupted. Clearing out the DB file works.
I have the full installer (including binary) installed. Since I have LP extension as a required extension in Google Suite Chrome extensions management required, to do a full uninstall, I have to disable this requirement. But alas, doing this, installing, and re-enabling the requirement, I still end up with the damn problem.
What a pain! This is basic stuff that needs to be reliable. Getting pretty damn upset with LP over the last few months of terrible application deployment.