WiFi connected with strong signal - internet won't work

[AC Question]

Help! I have a Samsung Galaxy S5 that has the most recent update. My WiFi says it is connected and has a strong signal, yet the internet and apps will not work unless I turn off WiFi. It is not the WiFi where I am now (at work), because it's been happening on my home WiFi as well. I've tried rebooting, forgetting and reconnecting the connection, changing from DHCP to Static, and checking the time/date. Nothing has helped. It has to be something with my phone, not the router. Is there a solution for this??