Hello dlcole. Have you found a fix? I tried reinstalling macOS and Xcode, the simulator reset command but to no avail.

I have the same problem but caused by the preview not the full simulator. I have to disconnect my hotspot (on the phone, NOT the Mac) and reconnect it to solve the problem and this has to be done every few minutes. So frustrating. A full Xcode reinstall did not solve the issue; neither did Network Link Conditioner or the simulator reset command from terminal. Any solutions would be much appreciated.