Using FSA funds to pay for dependent care expenses and qualifying for the Child and Dependent Care Credit are two different tax topics. You can still use your FSA funds to pay for dependent care.
For the dependent care credit, online classes still count if these classes are also available with the college/university she attends. In other words, if she is electing to take some of her course load via online rather than on campus. Education programs that are only online, would disqualify for the credit.
https://ttlc.intuit.com/questions/1900643-what-is-the-child-and-dependent-care-credit