[2D] Bug ground collision

I’m beginning with Unity, and I tried to do a base for a platformer game, in 2D.
I just have a caracter moving to left and to right, and he can jump.

I use some “blocks” to do the ground.

My problem is here :
My caracter moves perfectly, but sometime, he stop moving at the intersection of two blocks.
I don’t understand why, my blocks are perfectly aligned.

Someone know why? Thanks in advance!

(Sorry for my bad english)

I found the problem! My caracter only had a box collider. I added a circle colider for his feet, and it works!