talktalk email stopped working

[JACK27143]

I have a talktalk and a gmail account on my nexus 7. Recently I got a message saying cannot connect to talktalk server incorrect username or password.Talktalkhelp suggested deleting the account and re adding the account again. Now it will not allow me to re add my talktalk account I am getting message Cannot finish Can't connect to server(554 smtp.talktalk.net) My gmail account is working (imap) but not talktalk account (pop3)have tried setting the new talktalk account using imap settings but still get same message. my Talktalk account is still accessible on my PC using same settings