The frozen world and Wifi

When I was in another city, I could play calmly. But when I returned to my city, all the worlds were frozen. (The mobs stopped moving, the blocks are destroyed, but after a while they are restored ...At one point, I decided to turn off the Internet and the worlds started up. I use the Internet from a router. I don't know if this is a problem with my internet, just when I was in another city I used a different internet and everything worked. I am writing this post so that other people know how to solve this problem. And what would you explain to me whether it is a problem of my Internet or a game. I know this problem has already been resolved MCPE-123234 , but I did not understand how it was solved. And I think my solution to the problem will also be appropriate.