Google Calendar Integration Weirdness

Hello, I’m new to this, apologies for any stupidity.

I’m following the steps for Google Calendar Integration. Everything seems to work to the point where I get the Google ‘Success’ message that Home Assistant can now access Google - great! However, I go back to Home Assistant and after a few seconds it says that the token has timed out.

There appears to have been no changes to the Configuration.YAML and no new files in the Config folder. I have spotted the following in the logs though:

2022-06-10 13:56:03 ERROR (MainThread) [homeassistant] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/google/api.py", line 123, in _poll_attempt
    self._exchange_task_unsub()
TypeError: 'NoneType' object is not callable

I’ve tried creating a new Google Dev Project in case I did get something wrong there but when I relaunch the Integration Package in HA it doesn’t give me the option to change the Name & Passcodes like it did the first time. If it is caching that info somewhere I can’t work out where (tried a different browser, same result).

Any assistance very much appreciated!

Update: Found where the integration ‘user accounts’ are stored, cleared that. Entered the codes for the new Google Project. Same result. Google says ‘Yes, you’re connected’, HA says ‘time out or authentication issue’.

Update: It was IPv6!!! Simply turned off IPv6 (Settings>Network>Configure Network Interfaces>ETH0>IPv6=‘Disabled’) and it worked first time!!

I think I’m off on my HA journey now!