macOC desktop app errors with "Failed to Fetch" but only after awhile

When I start up the macOS desktop app, I can CRUD items just fine for a little while. Once the app has been running for a few minutes, I start getting a “Failed to Fetch” error.

I have tried deleting, re-adding, and re-trusting the certificate.

I have tried reinstalling the app, rebooting, then reinstalling.

I get the same error. But only after a little while.

Any ideas?