My mailbox is not opening already for 4 hours?

My mailbox is not opening already for 4 hours? I can log in successfully to Yahoo but when I click on "Mail" I receive the following message "Content Encoding Error! The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression." I am using the latest Mozila and tried also IE, but no result. My Yahoo is also working and I can see what e-mail were sent to me but I cannot access their full content. Thanks in advance!