Why won't my Google Email server connect?

Check if the SMTP server configuration is correct. You can connect directly to Google Mail using the settings shown below

 Outgoing mail server
 Use TLS

Otherwise, the issue is most likely that you need to enable less secure apps for your Google account.

Allowing less secure apps is required for authenticated SMTP (SMTP AUTH protocol) to work.

To enable SMTP AUTH for a single account:

  1. Turn on less secure apps in the Admin console.
  2. For the Google Email account you want to send emails from, turn on less secure apps.
  3. If you are using two-factor authentication for that account, create an app-specific password for use as a password in the Email Account connector.

After that, you should be able to authenticate using the respective account.

Important: You need admin rights in your Google Workspace organization to do that. Otherwise, ask your Google Workspace admin for help.

Further details: https://support.google.com/a/answer/176600