question Google and non-Google Domains

[Name Trader]

I'm trying to produce some email accounts, and I've hit a bump in the road.

I have 3 non-Google domains which I was able to add to my Google list of Domains. But have no idea how I did it
Is it possible to do this?

I have 1 of a set of 4 emails which is listed in my Google Domain Menu of my email accounts. But the other 3 just get rejected by Google, naturally so, since the address is not a Google Account.

I also have 2 emails on one domain in .biz (which are ancient) which happily list as Google Domains.

So I'm wondering how I managed to get 3 non-Google Domains listed in my Google Domains Menu, but not any other non-Google Domains. And if it's possible to convert them into Google Domains so they will appear on the Google Domains Menu?

Any ideas?

 

[Nodws]

try and initiate the transfer process, that should do it https://domains.google.com/registrar/transfer