Joining server issue

When I try to join servers that have worked before the most recent MC update, the game will say "Syncing Pack w/ server," then after a few seconds, it will say "Disconnected from server," and I'll have to try again or quit. This doesn't happen for all my servers, just most of them. I know I've got the right IP because it shows that the server is active. So what is happening, and how do I fix it, if I can? And also, my device is a Samsung Galaxy Tab 4 10.1