I recently purchased Minecraft for my Nintendo Switch and have found that every time I start the application, I am forced to sign in to my Microsoft account. Despite having signed in multiple times already. 
Also, sometimes I will go through all the steps, the game will show that I am signed in, and 10 seconds later it will say there was an error signing me in.

this is extremely frustrating because it won't allow me to use the skins that I have purchased due to them being linked to my microsoft account.