What is the certification supposed to lead to would be my question? Is it for work? Is it part of a degree program? Just a course your interested in taking?
If its work related or degree related you should check with your states, cities, or countries (not sure where you are) offices and make sure the course you are taking meets all the requirements for certification, licnesure, etc.
I went to college online, and recieved and accredited degree. Had that degree that took four year been through a university that was not accredited it would be a worthless piece of paper....although the information learned will stay with me always.
It really depends on your main goals at the end of your certification journey. Good luck.