Integration not loading after reinstall and backup restore

[Threesa]

Due to issues with Supervisor 2023.06.4 I had to perform a fresh install and reset my back-up.
However since the integration isn't loading anymore.

It's visible in integrations, but with a status "Not loaded", nor the option to reload.

In the logs the only (possibly) relevant thing I could find is this:
Failed to retrieve Access Token: ('Failed to retrieve access token: %s', KeyError('code'))