I was able to log in to my email account today. just today
--should I used the past perfect or the present perfect?
because it's no longer down. so should this be in the past?
The server had been down for ages.
The server has been down for ages.
It should be the past perfect because it was before you were able to open your account. If you use the present perfect, it sounds as if you still can't access your email.