issues with log in and load times

Hi all, 

The problem is trying to log in I'm using right credentials but come up with error try again but if i manage to get in then its really slow to load and when it doesn't all i get is this site cannot be reached (Ip address cannot be found ).

I've tested my internet, browser and firewall to see if any issues but all ok and not having any issues with other sites eg. amazon or google.

any help welcome

jonesy