Terraria Won't Launch (STEAM)

Hey! I have been playing Terraria recently problem free. Then I bought a game off of steam called The Astonishing Game and played it. After playing it, it seems that Terraria won't launch. I had a similar problem that happened out of the blue. I go to start the game, and the border around my avatar turns green like im playing the game and then it turns blue. Terraria tries to launch in the background but it crashes, leaving an error message:

6/29/2017 2:15:07 PM...

Terraria Won't Launch (STEAM)