Talktalk's status page says the issue is resolved but I still can't send or receive anything. I'm in the process of changing my login details for all of the web sites for which I have my Talktalk email as my login. Once I've don that I won't be tied to Talktalk any more.
To link this topic to your TalkTalk Mail service, in preparation for direct help from TalkTalk support, please check your Community Profile includes in Personal Information (Click here):
Your name, current TalkTalk landline 'phone and alternate number (mobile preferred). Add your full address with postcode (location). Then scroll down to Private notes to add email address(es), notes and references etc and then save changes.