Jekyll post not generated

Question

The post is not placed in the _posts directory.
When you change the collections_dir in your config from . (default) to my_col_folder all your posts have to move as well below my_col_folder/_posts jekyll defaults
The post has incorrect title. Posts should be named YEAR-MONTH-DAY-title.MARKUP (Note the MARKUP extension, which is usually .md or .markdown)
The post’s date is in the future. You can make the post visible by setting future: true in _config.yml (documentation)
The post has published: false in its front matter. Set it to true.
The title contains a : character. Replace it with &#58. Works in jekyll 3.8.3 (and probably in other ‘recent’ releases).