in reply to:
Thanks to your post about Webmentions I managed to prepare my blog to work with H-Cards and be ready to sent webmentions using Telegraph, and to receive them using Webmention.io, everything seems to be working at this time.
Thanks to all your effort I only took me two or three hours, but I am also stuck, at a different point of the one you were.
You should be able to get this post as a replay to yours.
I feel sorry that a simple trailing slash had you stucked for almost two days I think, I am an advocate of ending all posts with an .html extension, and only directories with a trailing slash, but it seems everbody likes the WordPress way and not the old times World Wide Web way.
If anyone want to implement webmentions in their static site, I really recommend you to read Basil's post