One of my clients is still using the legacy free version of GSuite legacy free edition
Prior to December 6, 2012, Google offered a free edition of G Suite—also known as the legacy free edition—that had a reduced set of business features. As of December 6, 2012, Google stopped offering the free edition to new customers.
I followed the steps in the Google FAQ to configure a group “[email protected]” email address (using Google Groups)
Unfortunately, I couldn’t get email posting from outside the domain to work. Every time I sent an email to [email protected] from an ‘outside’ email address, it bounced back:
After looking through all the settings, I saw Allow users to post to the group on the web was greyed out
It appears that this is no longer an option for legacy ‘free’ G Suite domains – as indicated by
> Web posting is currently enabled only on G Suite domains.