Cannot Get Mail The connection to the server failed.

My Yahoo e-mail has not updated on my iPhone 5 since 12/9/13. I have reset my Yahoo password. I have deleted my Yahoo email account from my iPhone 5 and added it again, but no luck. I don't know if this is a Yahoo isuue and I am not setting up my email account correctly on my iPhone or what is happening. Very frustrating not receiving e-mail! I would appreciate help with these issues. Thanks!