Have you tried checking the time and date are correct on the phone? This causes a lot of problems on Android if it's wrong. After doing that see if you can get back into the Play Store (why do they have to call it that? Terrible name).
You could also get the mobile provider to send you a settings file which usually fixes many connectivity issues. You have to send them a message but it wil be different depending on the provider.
Sorry I couldn't find anything for straight talk but you are basically looking for GPRS settings or something like that. I did find APN settings but that may not be what you need. You may have to ring them.
Are you using WiFi or mobile data? Check to make sure that your mobile data is turned on and if you're using WiFi make sure your network is working right by using another device to try to get on the Internet.
Another solution to most Android problems is to force stop the app from the settings > apps menu and then clear the cache but don't clear the data as that contains all your personal settings. If that fails you may have to also clear the data as well. Try to do the same for any other related apps which play videos on the device.