That's the answer -- the message at the top of the screen, which I could not see unless I scrolled up to look for it.

The specific error message is "You cannot delete an account that is associated with a Form 1099 box."

The community had previously provided the answer (found via a google search)

https://quickbooks.intuit.com/learn-support/en-us/employees-and-payroll/cannot-delete-an-account-tha...

Just performed the steps outlined in the link and it worked!