I can't open my yahoo inbox. Can you please help me?

I can log into my yahoo account but can do nothing else after that; I can only see how many e-mails I have in the junk, inbox, trash, and sent categories. This has been a recurring problem since last week. Only sometimes am I given the "clic yahoo" page option, which works. Otherwise, a yellow, triangular error sign appears at the bottom left corner (where "done" should ultimately show." At times, "done" shows, but nothing happens;it won't show me my actual inbox. I can't check my e-mails.