404 error on preview…「bufferuuid（29）is not valid（closed or unsupported file format）」

"Error: 404 Not Found
Sorry, the requested URL 'http://127.0.0.1:51004/view/29' caused an error:

'buffer_id(29) is not valid (closed or unsupported file format)'

Quick Fix 1: Remove Strikethrough Extension

Sublime Text > Preferences > Package Settings > OmniMarkupPreviewer > Settings - User
paste the following to remove the strikeout package.

{
    "renderer_options-MarkdownRenderer": {
        "extensions": ["tables", "fenced_code", "codehilite"]
    }
}
Quick Fix 2: Fix the Strikethrough Extension (if you need it)

Find the python-markdown sublime package.

On the Mac: subl "/Users//Library/Application Support/Sublime Text 3/Packages/OmniMarkupPreviewer/OmniMarkupLib/Renderers/libs/mdx_strikeout.py"

Replace the makeExtension() method with the following:

def makeExtension(*args, **kwargs):
    return StrikeoutExtension(*args, **kwargs)
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