If playing using the PS4 Remote Play feature, when launching Minecraft, it is unable to sign into the PlayStation Network, the button will appear on the main menu screen to sign in, but selecting it will do nothing at all & will not allow you to sign in.

Launching the game directly (so not using RemotePlay) will then allow the game to successfully sign in, and in pretty much all cases, will automatically sign in each time.

I've tried deleting all user data for Minecraft to test this issue, as well as a fresh reinstall (the copy is a digital download), and each time when trying to launch the game and sign in using RemotePlay, it will fail upon signing into the PlayStation Network, and as such, will also then fail signing into your Microsoft Account.

Again, in all similar scenarios, when running the game locally on the system and not via RemotePlay, it will sign in correctly each and every time.