Jekyll post not generated

Question

I am trying to add a new post to my Jekyll site, but I cannot see it on the generated pages when I run jekyll serve.

What are some common reasons for a

Answer 1

My post also did not appear an the error was, that in my name I used a dot, e.g. 2017-10-18-test.2.md.
This is not accepted, you have to use 2017-10-18-test2.md.