When I tried to check my emails, I could not connect to yahoo mail. I kept getting the message that the phone could not connect to the yahoo mail server. I just happen to go to settings / wifi and checked what network I was connected to. When i did, i found the password was missing. When I reset the password, I was able to get my iPhone to connect to the yahoo mail server. It maybe that the phone is unable to connect to the router. Sorry, I am not being more helpful with all the right tech terms. You need a password to log on to your email. You also need a password when you log onto your Internet through the router