Just from a quick overview it seems that the issue might lie withing the URI connections matching rather than on the API versions.
Are there any more error or logs information that you can see? That would help get a little more insight into the issue.
It seem like facebook is saying something about the domain of the url not being included? Could you maybe share the whole message?
In the meanwhile I’d say you might want to verify if the OAuth redirect url configured in your Facebook App matches the one specified in n8n. I think you can find this in your Facebook login section under “Valid OAuth Redirect URIs”