can't login to Minecraft pocket edition after update

can't login to Minecraft pocket edition, when I just downloaded the Minecraft PE application, login to with my account Minecraft runs smoothly, but the login for my account is interrupted when the application detects a world file on my cellphone, at that time the application exports world files to be applied to Minecraft, when it's finished I was told to exit the game (restart), when I return to the application I can't login again (code : ghast)