Can't add email account

I had some issues with my iPad (app draining battery) and after running diagnostics etc. the guys in the apple shop advised that the easiest solution was to reboot as a new iPad and only install the wanted apps (I needed an app clear up anyway!).

I've set up my iCloud and iTunes accounts with no bother but I can't get my emails to work. I've entered all the details as instructed (and as I did before successfully on my iPad and iPhone) but I get a message saying my username or password is incorrect. It's most definitely not as I have checked and checked and checked. I have no problems accessing my mail over the website and my phone is still attached to the account, but my iPad will not accept my username and password! I've deleted and re-added the account countless times and saved the account and triple checked all the settings which are all completely correct

Please help! The amount of time I'm spending trying to fix this is using so much battery life that I may as well have not bothered with the reset! :)

what type of email account is it?

It's with sky, apparently it's gmail, but tried adding that way and it doesn't recognise my details that way either. Sky say add it as an 'other' account.......I've done it before with no problems, just won't work now!