How can I remove this seam down the middle after mirroring? Yo,

I'm new to Blender and I'm trying to make a humanoid figure. I followed this tutorial. I have completed one half of the character but when I mirror it there is a seam down the middle. Clipping is on, too, and all the answers I found are to do with turning it on. I'm stumped.



Thanks in advance,

M~
I think the vertices that should be in the middle of your character, are slightly beyond the axis, like that :


In Edit mode, select all your vertices (A) and move them to the left* until they "stick" to the mirror axis (this is what Clipping does).

*left in my example, maybe right in yours