STATUS_CODE_ERROR

I am having an error every time I try to login to be able to download updates in my mac book pro.

I bought it in December 2014 and everything have work until today when I got this error STATUS_CODE_ERROR.

I checked if my password was wrong by going to Icloud, and I saw that I am putting the right password as I login right away to icloud from safari.

I tried several times and as I got frustrated I decided to change my password by clicking forgot? in the Appstore app in my macbook, but I got this error

Http/1.1 Service Unavailable.