Error messages when sending test email

Hi there,

I’ve just tried your plugin, Post-SMTP, using our Gmail account and got a client ID etc.
I sent a test email and it said it went through, but it never arrived.
Here are the error messages I got:

Postman is not configured and is mimicking out-of-the-box WordPress email delivery.
Postman will send mail via Sendmail (server defualt – not SMTP) to localhost:25 using no authentication.

You have configured OAuth 2.0 authentication, but have not received permission to use it. Grant permission with Google.
________

I went to the Grant Permission link and this is what I got:

Authorization Error
Error 403: access_denied
The developer hasn’t given you access to this app. It’s currently being tested and it hasn’t been verified by Google. If you think you should have access, contact the developer ([email protected]).

Could you help sort this out?
Thanks!