Cannot Combine all AT&T accounts to one ID

From AT&T “Go to my account”, I selected -

“Combine all your AT&T accounts to one ID”

I was able to link one of my email subaccounts without any problem.

When I try to link a second email subaccount, I keep getting the following message (for over 3 weeks now):

"Sorry, but we can't combine [email scrubbed] with your first ID, yet. We're adding more accounts you can combine into a single ID, so please try that ID again later."

I can still access the second email subaccount on my phone, but when I try to access it from my desktop using MS Edge, I get this message:

Looks like you’ve tried to sign in unsuccessfully too many times. Recover your ID or reset your password to continue.  CARE CODE: 205.2 [LU003]

What do I need to do to access the second email subaccount on desktop using MS Edge?