Can't add Gmail to my email accounts on my Mac Workbook Pro

Hi everyone,

I am trying to set up my gmail account on my mac workbook pro using the usual route:

but I keep getting a message stating:

Authorisation 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.

You can let the app developer know that this app doesn't comply with one or more Google validation rules.

When I request details, I get this message:

The content in this section has been provided by the app developer. This content has not been reviewed or verified by Google.

If you’re the app developer, make sure that these request details comply with Google policies.

• • redirect_uri: urn:ietf:wg:oauth:2.0:oob

I have had my gmail account on my pc for a long time but deleted it yesterday because I couldn't get it to accept the new password I wanted. Now, with that new password, I want to reinstate it, but each time I click on google I get the above messages. As gmail.com is an account of google itself I cannot see why it isn't compliant - or is it something on my PC that causes this, and what can I do to remedy it?

Can anyone help please?

Thank you,

Lesley