If you get the error when signing in to your G Suite Admin console, you might be trying to sign in with a personal Gmail email address. Regular Gmail accounts cannot be used to sign in to Admin.google.com, due to which you are facing a G Suite login problem. So, replace it with an admin.google.com address linked with your managed Google Account, G Suite, or Cloud to sign in to the admin console.
Read also - Why G Suite not Receiving Some Emails
Gmail not sending emails
Read also - Why G Suite not Receiving Some Emails
Gmail not sending emails
