Cannot grant Google Permission

Hi there,
I followed the steps at (https://wpmailsmtp.com/docs/how-to-set-up-the-gmail-mailer-in-wp-mail-smtp/) and set up the plugin. I doubled checked the Client ID and secret id multiple times and it’s using the right Google account.

Once I hit Save settings, the instructions state:

After saving your settings, the page will refresh. You must grant permission before Google allows our plugin to use your Gmail API to send emails.

To do this, scroll to the bottom of the WP Mail SMTP settings page and click the button labeled Allow plugin to send emails using your Google account.

The button Button simply doesn’t appear on my screen. There are also no further steps in the wizard.

When I try to send a test email, I get the following:

Versions:
WordPress: 5.8.2
WordPress MS: No
PHP: 7.4.25
WP Mail SMTP: 3.2.1

Params:
Mailer: gmail
Constants: No
Client ID/Secret: Yes
Auth Code: Yes
Access Token: Yes

Server:
OpenSSL: OpenSSL 1.1.0l  10 Sep 2019
PHP.allow_url_fopen: Yes
PHP.stream_socket_client(): Yes
PHP.fsockopen(): Yes
PHP.curl_version(): 7.52.1

Debug:
Email Source: WP Mail SMTP
Mailer: Google / Gmail
{
  "error": "unauthorized_client",
  "error_description": "Unauthorized"
}

I’m not sure how else to authorize Google.

The page I need help with: [log in to see the link]