Redirect_uri_mismatch on localhost setup

Being new to most of this I chose to try it out first on a locally hosted WP installation.

Postman reports all set up, but on getting authorisation I receive the uri mismatch error with detail:

“The redirect URI in the request: http://localhost/wordpress/wp-admin/options-general.php?page=postman did not match a registered redirect URI.”

Settings are:
Type:SMTP
smtp.google.com:587
STARTTLS security and OAuth 2.0
Javascript origin: http://localhost
Redirect URI: http://localhost/wordpress/wp-admin/options-general.php?page=postman

Can you tell me what I am missing/misconfigured?

Thanks, Julian

https://ww.wp.xz.cn/plugins/postman-smtp/