Can not sign on

It takes us over 20 mins to long into Minecraft. Sometimes more.
Stays as a black screen for a long time and than the red screen with Mojang stuido for A longer time as well. Than wont let us log in and sends us a screen that has an exclamation point and says we can log on. We have not been able to log on for over 2 weeks. 

Affects version i am unsure of.