"The specified user does not have a valid profile" error message when trying to open the new launcher

Basically, yesterday, everything with the launcher and the game was working just fine. But today, I decided to play Minecraft but to my surprise it gave me an error. I have no clue as to what caused this, I didn't update my system, Java, Minecraft. Nor did I mess with any settings or files. I have been using the new launcher for 5 months.

What I expected to happen was:
The (New) Launcher to open properly with no issues.

What actually happened was:
I get an error saying "The specified user does not have a valid profile".

Steps to Reproduce:
It randomly happened, I have no idea.