I only want users to be able to submit business email addresses but also validate their email addresses to prevent an invalid email address from being submitted.  I was given the regex ^(?!?^@\s]+@(gmail|yahoo|hotmail)\.com$)$^@\s]+@+^@\s]+\.\a-zA-Z]{2,}$ to add as a custom field but this seems to have stopped working. Can anyone help with another regex suggestion?