Welcome to the forums.
I have just been looking at the TalkTalk help page for setting up email on an Android phone, http://help2.talktalk.co.uk/email-setup/setting-ta
From my experience the specified combination of settings [POP type account, outgoing server security set to TLS, outgoing server port set to 587) does not work.
Try using those server settings with an IMAP account, or for a POP type account use outgoing server security set to none, and outgoing server port set to 25.
I have tried many email apps on my android devices for one that 'just works' across all of my email accounts (hotmail, live mail, yahoo mail, gmail, talk talk, and my own email servers from my websites) and have found a great many lacking.
The built in email app in android is trully awfull for anything other than a gmail account and should be avoided anyway.
The best mail app I have used (and the one on all my android devices) is this one;
and best of all it didnt even need my intervention to set up all of the accounts, just email addresses and passwords and that is the only app to ever have done that..