1) If you are receiving this error, a common problem will be that the DNS records required to have Google App Email work are not setup or not setup properly.
If the problem still occurs and the DNS records are correct move onto step 2.
2) After logging into your email (as an admin) and receiving the "This Service Is Not Available" message try this link first:
If you do not arrive at the dashboard try this link:
3) One of the above links should work.
NOTE: If you do not use your domain name in place of the red placeholder above, the links will not work.