I updated to IOS 6.1 and now cannot send email

Updated my iphone 4 and ipad2 to IOS6.1 now I cannot send email. i can recieve it but not send it. We have 2 other iphones in the house, they didnt update and can send no problem (naturally they wont be updating based on my experience) but I'm left in a jam. Have been through every setting on the accounts side by side and they are identical the only thing that is different is that I am running Ios 6.1. is there a way to go back to IOS 6 my mail worked with that?