If I recall correctly there were a few issues from older firmware versions that had to do with resolving hostnames. Are you on 18.211.2? Think I saw this happen in the 18.107 versions.

Firmware? Make sure you have latest stable. Sometimes beta versions will cause this issue. We had it happen to our APs.

If they're refusing to provide information, the MSP almost have to be the owners of the hardware. If that's the case, Refer to the contract you signed with the MSP and see if they have an obligation to provide you with that kind of information (which...

My apologies, I need to read better. For "Flows Deny", I am 99% certain that it's going to be an inbound connection from an external IP. We get tons of them every day. I can't give you any other information on Syslog. We let our SIEM translate it. I'...

I know this isn't what you want to hear, but we've had this issue before and ended up factory resetting the switch. It then worked. Try what the others said first. 100% worth a try.