Failed to create activation request

Just got off the phone with Apple tech support. The following link was sent to me as a way to request activation lock removal:

If you need help removing Activation Lock and have proof of purchase documentation, you can start an Activation Lock support request.

I have the same problem with my 2019 MacBook Air. The previous owner removed it from the device list in her iCloud account yesterday. But I'm still locked out in the same <Activate Mac> screen.