Unable to configure Apple TV - does not accept PIN

Describe the bug

While trying to add ATV to integration cannot pass the step of entering the PIN, but it is not accepted. Configuration wizard displays message:

Pairing
Pairing is required for the RAOP protocol. Please enter the PIN code displayed on 
screen. Leading zeros shall be omitted, i.e. enter 123 if the displayed code is 0123.
Invalid authentication

After evry retry new PIN is displayed by ATV, but none is accepted by integration. Every retry logs error in homeassistant.log - listed below

Error log

021-12-18 14:39:59 ERROR (MainThread) [custom_components.apple_tv.config_flow] Authentication problem
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/pyatv/support/__init__.py", line 33, in error_handler
    return await func(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/pyatv/protocols/airplay/auth/legacy.py", line 62, in finish_pairing
    await self._send_plist(
  File "/usr/local/lib/python3.9/site-packages/pyatv/protocols/airplay/auth/legacy.py", line 79, in _send_plist
    return await self.http.post(
  File "/usr/local/lib/python3.9/site-packages/pyatv/support/http.py", line 359, in post
    return await self.send_and_receive(
  File "/usr/local/lib/python3.9/site-packages/pyatv/support/http.py", line 412, in send_and_receive
    raise exceptions.HttpError(
pyatv.exceptions.HttpError: HTTP/1.1 method POST failed with code 500: Internal Server Error

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/config/custom_components/apple_tv/config_flow.py", line 424, in async_step_pair_with_pin
    await self.pairing.finish()
  File "/usr/local/lib/python3.9/site-packages/pyatv/protocols/airplay/pairing.py", line 74, in finish
    await error_handler(
  File "/usr/local/lib/python3.9/site-packages/pyatv/support/__init__.py", line 41, in error_handler
    raise fallback(str(ex)) from ex
pyatv.exceptions.PairingError: HTTP/1.1 method POST failed with code 500: Internal Server Error

How to reproduce the bug?

I receive this error every try to add ATV to HA.

What is expected behavior?

Completion of configuration wizard.

Operating System

Mac OS 12.0.1

Python

3.9

pyatv

2.2.0

Device

Apple TV 4k, TV OS 15.2

Additional context

Not sure about python version, using supervised HA in VM under ESXi. All the lates update, so assuming the latest version of python too.

[postlund]

@Colorado4Wheeler I think we found the problem. For some reason there’s an old entry lurking around in .storage/core.config_entries for your device. I don’t quite understand why this isn’t visible in the frontend, but if you remove that it will work again.

[Colorado4Wheeler]

I’ll take another look but when I manually purged everything from core.config_entries before (when you posted that it was needed generally for the update) I was pretty thorough.