Help with Claws Mail and OAuth2

Hello,

A very big thank you to the Claws Team for a great eMail Client! :)

I have been trying to set up OAuth 2.0 for Gmail in Claws Mail v3.18.0 (Windows Version)

I have followed the guidance in https://www.claws-mail.org/faq/index.php/Oauth2, and
reached the stage of filling in a ClientID and Client Secret.

But when I try to obtain Authorization, it reports

[quote]
Authorization Error
Error 400: invalid_request

You can't sign in to this app because it doesn't comply with Google's OAuth
2.0 policy for keeping apps secure.
[etc]
[endquote]

This appears to be related to having chosen "restricted scopes", leading to Google
having to verify the App, which their help says can take 3 to 5 days.

Can anyone tell me, please, whether this is the expected behaviour?

Thank you.

Kind Regards,
Rosemary Lockie