iPad mini 5 Files app not connecting to AirPort Extreme shared disk.

I have a SSD attached to our AirPort Extreme via USB port that all the Macs in the house can use. All Macs have working wi-fi and all users can access the shared disk with AirPort device password.

I cannot get Files app in the iPad mini 5 I just purchased to connect to it. It is connected to the Internet through the AirPort with email and Messages working fine.

Here's what I tried so far:

Identified the smb address at smb://10.0.1.1.445

In Files app>Locations>Connect to Server prompts for smb address, then touching Connect presents a window requiring either Guest or Registered User. When selecting the latter you then have to enter Username and Password.

The pass should be the AirPort device password as configured in the Disks tab of AirPort setup. All other Macs use this password to successfully connect to the AirPort attached drive.

However, it requires some entry in the Name field to un-grey the Next button. I've tried the iPad Name, AppleID, and multiple computer usernames of connected Macs and when I touch Next the result is always "The operation couldn't be completed. Operation not supported."

I also tried changing the methods authentication for the Shared Disk Access, to Accounts, and Disk Password. Even tried enabling Guest network and the credentials I set for it also don't work on the iPad.

I'm stumped at this point and need some suggestions.

iPad mini 5 is running 13.3.1 and the AirPort Extreme is on firmware 7.8.1 which is reporting latest.

Thanks for any help. Mom and I both got our first iPads and we're slogging through the setup waiting to get to the fun part.

JH