change apple id with a G suite email

Hello there, Im trying to change my Apple ID from an email with @icloud.com to my GSuite email.

But when I try to change on iCloud.com after it sends me a verification code to my Gsuite email, is says:

 "This Apple ID is already in use. If you have an email address ending with @mac.com or @me.com, it is already an Apple ID. To sign in with it, simply enter the email address and password. Or you can create a new Apple ID using a different name."

I tried to use the "forgot my password method" but nothing, it says that my g suite email it not belongs to an Apple ID account ...

I have to mention here that this is a new g suite email, I haven't used it anywhere...

How can I solve the problem ?