okay on my pc. press top left start icon, select e-mail icon. buttom right, select menu, options, tap on your name of your email account, tap edit account setup, keep pressing next until you get to outgoing smtp mail server, hit advanced server settings, on netowrk connection scroll thru and change to either your mobile operator internet connection or the internet.
if this fails, delete email account. from home page, email tab, menu add account. Even if its gmail, select other and enter your settings, dont use the google mail option.
Next goto settings tab, menu, all settings, connections, connections, manage connection, proxy settings, make sure 1st box is ticked but unticked for "this network uses a proxy server to connect to the internet".
Try each one in order, seeing if on adjustment works. The proxy item I found if ticked stopped twitter working using tmobile uk.
My tech blog http://http://www.gavinsgadgets.co.uk
- massive HTC One review
Current Devices HTC One, Nokia Lumia 620, BB Curve - Previous Note 2, iPhone 5, Samsung S3, Note, iPhone 4S