Configure PFSense Firewall for wifi users and mobile apps

we have a pfsense firewall that I need a few settings changed. The pfsense is 2.3.3 and runs proxy server. I have about 8 user accounts. In general, it works great. the problem we have is some of the wifi users on mobile phones apps are not working, ie gmail, facebook snapchat. The users can access these sites via the browser on the phone but the apps won't work. We would also like to block a group of users at certain times.