Access database repair to accept longer emails

I have an enrolment system built in Microsoft Access for the Global Enterprise Experience which is currently receiving enrolments. However if email addresses exceed 30 characters in either the main email entry, alternative email entry, or the recommender's email entry, then it produces an error message saying that there is too much data for the field. I have changed the software to enable it to take up to 255 characters, but this has not taken effect. There must be some hidden code that is preventing the Access software from going beyond 30 characters. I urgently need to have this enrolment system fixed, and am looking for someone who is confident they know where to find the problem. Students can enrol as a single or a pair. The second enrollee enters their partner's email address and then the enrolment continues exactly the same as if there was a single enrollee.