openmailbox went to shit months ago when they abanonded their original free email supported by user donation thing and replaced it with a commercial service
they gave no warning or notice and shut down their email for a week+, and then came back up with the current bullshit. it's been garbage ever since.
their email hasn't been working right for the past month now for the people who are still on it. they have no support even if you are dumb enough to pay either. use openmailbox at your own peril.
if you need an immediate alternative protonmail is reliable, weather or not you believe in their javascript encryption. no imap unless you pay but your not getting that from openmailbox either.
do not rely on openmailbox for literally anything of any importance and do not give your money to openmailbox. i expect it will disappear completely in a year or so. they've fucked their existing customer base so hard they now have a terrible reputation.