Failed to load my Minecraft worlds

I have several worlds in my Minecraft Bedrock game, after a while since I played very often, one day I got in, and all my worlds appeared in gray as if I had not used them for a long time, I thought that my worlds were they had lost, but I saw that Minecraft was still weighing the GB of all my worlds, I installed an Xbox application to copy and paste the world again and it did not work, I checked on Youtube and there is no solution either, I do not want to know the fact that I will lose all my worlds, since I have spent a lot of time in this one, thank you.

 Data that may be useful:

 1-As soon as I want to put the world put: Synchronizing user data, this may take a few minutes;  A few minutes later it stops loading and I get a message saying Failed to sync world data, do you want to try again?

 2-I moved the game to my external hard drive from the Xbox, it didn't work and I moved it back to the Xbox from the external hard drive