Can't access Internet for apps?

[Android Question]

I realize this is probably a dumb question, but I can't seem to access the internet under certain conditions. For example, my google plus account doesn't work; it tries to load for a long time and then tells me i cannot connect to the server.

Same thing with lookout; trying to get it set up and i get an error message that says I cannot connect to the server.

By contrast, apps that require me to use the internet seem to work great (like Facebook or Twitter).

I just got the phone today so I'm probably missing some crucial step, but I have no idea what would cause it to act this way. I'm on a home network, should be no restrictions to anything, etc.

Model number is SGH-T769, running 4.0.4

Thanks!