I'm trying to get rid of warnings about "the recipient xxx@yyy.com does not belong to your organization", which shows up for me pretty much every time I reply to someone not in my contact list.
https://support.google.com/a/answer/7380041 tells me to look at Apps / G Suite / Gmail / Advanced settings, which is fine, but I cannot find anything about "Unintended external reply warning" on that page, and there is nothing about how to "Select your top-level organization" either.
For me, the Advanced settings page has three tabs: General settings, Email addresses and Labs (titles roughly translated from Swedish), and neither of them mention anything about "unintended externaly reply" (in any language 🙂
Edit: this is on a free account
Best Answer
I am also having this same issue. One of my G Suite accounts has many more options at the top, as seen here, which includes the ability to disable the "Unintended external reply" warning:
However my other G Suite account does not have these options, and is missing several others, as seen here:
I will note that the latter account (without the options) is the older of the two, which was grandfathered in under the FREE option...which could be a factor.