Not able to link server and jumped back to the home page of my phone

First problem: I tried to join servers in Minecraft, but it said it is not able to join because of my settings, it guide me to the Xbox.com, but i could never found the place to change to settings.
Second problem: Sometimes when my phone is loading Minecraft, it automaticlly jumped back to the home page of my phone(sometimes!)
I am using on a Samsung Galaxy C5.