Yesterday I started having an issue where I can no longer receive chat messages in either the phone or desktop app...kinda. When someone sends me a message it will appear on my phone as a notification, but if I go to check the chat in either the phone app or the desktop app, the message is not there. I have restarted and signed in/off several time to see if that would reset things, but to no avail. Tested again this morning and still having the same issue. Very frustrating as I have no idea how to troubleshoot something like this.
I am having this exact issue and tried the same troubleshooting. It's been going on since last week off and on. I couldn't find an answer on the Support page. I hope someone monitors this Community and helps because my company uses Chat extensively. I'm afraid I will me an important message.
On Dec 7th, there was an issue reported that is similar to what you are both stating. This can be found on the Zoom Status page. You can subscribe to notifications via the page as well. The link is below. There are some updates that are being pushed out this week/weekend. You can read about them on the status page as well. I've not seen anything in notices about impacts during updates but please post if this is still an issue.