pandoc “cannot parse yaml header” when converting md to pdf

I am trying to convert a markdown document to pdf using pandoc, and it was working fine until it just started to show an error:

pandoc: Could not parse YAML header: did not find expected alphabetic or numeric character "source" (line 32, column 85
pandoc: YAML header is not an object "source" (line 17, column 1)
pandoc: Could not parse YAML header: did not find expected alphabetic or numeric character "source" (line 8, column 91)

Lines 32 and 8 are blank lines between paragraphs, and all that's on line 17 is "---".

I don't even know what YAML is, but I don't want to use it, just MD->LaTeX->PDF.

Searched for these errors but could only find stuff mentioning YAML, not the errors.

Any help would be appreciated.

See http://johnmacfarlane.net/pandoc/README.html#yaml-metadata-block

There must be something in your document that looks like a YAML metadata block, but isn't. Such a block would start with --- on a line by itself and end with --- or ... on a line by itself. The line numbers in the error message refer to lines inside the metadata block, not to lines of the document.

By the way, you can turn off YAML metadata block parsing entirely by putting