204: Link expected to point to a file

You linked an image with [i]-> or other media files with [v]-> or [w]->. The arrow is supposed to be followed by the path of a local or remote file or of a data URI. In your case, the arrow points at a hash #, which marks a target on the same page, or at a question mark ?. This is invalid.

Solution

Make sure to point the link at a file:

[i:my companion looking suspicious]->mutt.jpg

For images, a second link may link from the image to a target on the same page though:

[i:my companion looking suspicious]->mutt.jpg->#dog

In case of other media files all links must point to actual files, for example:

[w]->https://example.org/trailer.mp4

[v]->poster.jpg->movie.mp4->subtitles.vtt

Rename the file, if an actual filename literally starts with # or ? in your case.