Some users experiencing issues using Gmail over IMAP, Google working to fix

Google is aware of the problem and is working on a fix. The issues seem to only be affecting those using Gmail with an IMAP mail client, and results in error messages and other problems. These issues shouldn't affect those using the Gmail app or Gmail on the web.
From Google:
We're aware of a problem with Gmail affecting a significant subset of users. The affected users are able to access Gmail, but are seeing error messages and/or other unexpected behavior.
Google plans to offer an update on the situation soon. The company first started investigating reports of a disruption this morning at around 10:20 a.m. EDT, and expects to issue an update on the situation by 12:15 p.m. EDT, though they note that this time could change.
Source: Google
Master your iPhone in minutes
iMore offers spot-on advice and guidance from our team of experts, with decades of Apple device experience to lean on. Learn more with iMore!
Joseph Keller is the former Editor in Chief of iMore. An Apple user for almost 20 years, he spends his time learning the ins and outs of iOS and macOS, always finding ways of getting the most out of his iPhone, iPad, Apple Watch, and Mac.