If you are using Google Chrome, ensure that you use the most up-to-date version [Version 61.0.3163.91 (Official Build) (64-bit)].
Within Google Chrome, follow the following steps:
1- in the address bar type: chrome://settings/
2- click on ‘advanced’ (at the bottom of the page)
3- under ‘privacy and security’, click ‘content settings’, and then ‘flash’
4- ensure that the option ‘allow sites to run flash’ is ON and the option ‘ask first’ is switched OFF.
It may also be advisable to add https://nyu.globaldentalschools.net to the ‘allow’ column.