Ok, I have restarted my 4S twice now and still can't receive/send emails. Any other suggestions?

If you remember your email password information:

Try to remove the email account from the device and re-add the account.

More Info Here > Unable to send or receive email

From Here > http://www.apple.com/support/iphone/mail/

Hi Friend,

Which kind of account you are using?

If you are using a business account （ for example stevejobs@apple.com) you must set POP account info properly, filling all the blank fields (name, email address, description, password, Host Name, user's name, SMTP). Just one field blanked causes error in sending/receiving.

If you are using a default account (iCloud, Yahoo!, Hotmail...), fill all the blanck fields (Name, Email account, Password, Description） and sign in.

If not works, delete the account and sign in again

Hope it will be helpful