User Can't Stay Connected on Personal Phone to Company Guest Network

Hi Apple Support,

I'm very aware that there's potentially a local network issue, but I'm just trying to rule out that there aren't settings on the iPhone 13 OS Version 15.4.1 that might prevent a user from getting on and maintaining access to our company's guest network that I hadn't already considered.

The user either can't get into the guest network at all saying that there's "No Internet Connection", but no one else in the building reports the same issue. If the user can connect, the connection will randomly disconnect.

The iPhone's built in VPN is off, restarting the phone doesn't resolve the issue, iCloud private relay is off, and wifi assist is off. The only work-around I've found that helps some is to put their phone in airplane mode and then when airplane mode is off it'll connect again for a random period of time before dropping the user again.

Other than suspecting there's an issue with our guest network, is there anything else you'd suggest I try or rule out on the user's phone?

Thanks!