iPhone 16 Pro won’t connect to local IMAP server

Attaching to an IMAPS or SMTP server with an interface on a private IP address to a local server on the same private subnet using the default mail client no longer works. It just hangs on “Connecting” in perpetuity as long as it’s tied to the WiFi private network. DNS resolves internal IP just fine. There is no “local network” permission in iOS for the mail client, so that didn’t fix.

Turn off WiFi? Perfectly fine against the public address. Works like magic.

I’ve rebooted the mail server and the DNS servers locally.

Anyone else having an issue contacting a local IMAPS or SMTPS server?