page not found error when submitting comments

I can’t find anything answered that quite meets this issue.

On attempting to submit a comment to a post the user is given a page not found error. Ive tried several different themes, deactivated all plugins(only about 4 used) and tried different devices & browsers with the same result.

I can’t see anything in my setup that would result in this. I don’t know how long it might have been happening as I haven’t blogged in a while. I am just trying to revive it and it would be nice to have the comments available.

site is http://www.scrollchristianbook.com if anyone would like to test it. I’d certainly like some ideas of what to look for.