Can't log in to xperial mobile email app?

[robbocop33]

Can't log in to standard Sony xperia email app. This has happened many times before, just decides not to log in to the server, but 'always' rights itself after it's had it's hissy fit.
Today however it's digging in it's heels, i just can't connect today, username and password are same they've always been, i deleted the account and tried to manually setup the account again, it just won't work!
Anyone any ideas? Thanks.