Phone can not reach yahoo server

I get the message that yahoo can not connect to the server. As was suggested online, I put the correct password in and it verified it. When I went to check my mail, I got the same message. I went back to the settings and the phone put my old password back. I have tried turning the phone off and on again, have put my correct password in 5 times but still can't access the server. The odd thing is I changed my password over 4 months ago, and had not had any problem until now.

I am not sure if it matters, but I have not upgraded to the newest IOS because there is not enough room on my phone.

Does anyone have any suggestions? Thank You!