Tap "Save" — wait for the judgmental spinning wheel
"Cannot Verify Server Identity"
Apple, in its infinite wisdom, doesn't trust your server. After all, you didn't pay $999 for a certificate.
Tap "Details" → "Trust" → question your life choices (for buying Apple products).
* Requires iOS 14 or later. Earlier versions may require sacrificing a Lightning cable to the gods of Cupertino. Certificate trust settings buried deep in General → About → Certificate Trust Settings, because Apple knows best.
Contact: admin@kubasek.vip
This document is by no means complete... ask Monty if you're stuck.