I narrow it down:
ebook-convert test.md test.epub
with the attached test.md file works.
ebook-convert test.md test.epub --line-height "22"
leads to the described error, when uploading the test.epub file to http://validator.idpf.org/
I also attached the screenshots of the test runs:
I narrow it down:
ebook-convert test.md test.epub
with the attached test.md file works.
ebook-convert test.md test.epub --line-height "22"
leads to the described error, when uploading the test.epub file to http:// validator. idpf.org/
I also attached the screenshots of the test runs: