Check with your ISP to make sure they’re not blocking port 25 (outgoing) or port 110 (incoming), or check your router or firewall to allow traffic on that port. Also check your antivirus software any settings that may relate to e-mail. Depending on which company provided you with the email account, some companies use different ports to access the mail on the server. A Google search will usually come up with an answer to this, but you may have to contact your internet service provider.
Can’t Send Mail Via POP On Yahoo Mail!