I'm noticing that my AirPrint installer does not seem to hold the value of the "Allow Blank Password" checked. Every time I reopen the AirPrint_Installer.exe the check box is unchecked. I have yet to get the lock removed.
It's been a while since I've tried them, but the iOS 10 devices no longer see the AirPrint printer, while my iOS 11 device does, just with the lock on it, and it hasn't prompted me for a username / password. The forget option in the phone does not seem to be working either. I'm resetting my network settings now. Nope. Still got the lock, and doesn't prompt me.
One other thing got me thinking I may not be following the procedure correctly. When I click "Update" in the installer, I get a message: "You may need to restart your ___ for these settings to take effect." There's no "___" though. I have only restarted the service so far, but it seems it's time to give the whole computer a try. Well, I haven't done that yet, but
Set service to run under AirPrint user, and then switched it back to local system.
I did somehow get my iOS10 device printing again, getting prompted for a username and password, but since the AirPrint user now has no password, it's easy to type.
Both firewalls are currently off (not exactly feeling high-security at the moment!).
OK. Repeat the steps above: stop service, Admin CMD prompt, Open Installer as an admin, (notice box still not checked). Clicked update. Got the message that something mysterious needs a restart. Service is not running. So I will click "Start" in the installer app. OK. It's running, but didn't say running, even after a refresh. Was it really not running? Well, it's running now. Now let's go into the iOS11.2.6 device for at test. Ahh... Why not reset network settings. Same old stuff. Connection can not be verified.
I guess it's time to restart the "server" (window10 pro single user license).
OK. After a reboot, the behavior is the same. ios10 works, same lock and message from ios11.2.6 Now resetting network settings on the iOS11.2.6 device. No dice. Same behavior after reset network.
I give up again.
Edit: I just tried adding a password, and the ios10 device works fine, prompting for the username and password again as the credentials were clearly no longer any good. The iOS11.2.6 worked the same as with the blank password. I wonder if the TLS or the other protocols mentioned made the difference.