Google+ is now only available for G Suite customers and it is no longer available for consumer (personal) and brand accounts.
Learn More: https://support.google.com/plus/answer/9217723

G Suite customers may see some changes to Google+ features related to the consumer
Google+ shutdown. You can talk to your G Suite administrator to learn more
(https://support.google.com/a/answer/6208960) or you can find more details here:
https://support.google.com/a/answer/9229693.

You can also expect a new look and new features soon. Learn more:
https://cloud.google.com/blog/products/g-suite/new-enterprise-grade-features-in-googleplus-help-businesses-drive-collaboration