@ben @dan
There seems to be another upload problem with parts of the CMS on the server.
I created a very simple CMS item with the corresponding .md file and frontmatter.
When I test everything locally in the browser, all the “placeholders” are displayed correctly.
However, as soon as I upload everything to my server, I only get the message “No item found”. Where should I start looking for the cause?
project-file: elementsapp://downloadDocument/uQ71YWDCrFwt
Not that it helps, but I downloaded your project and tried it out.
As you say, the page displays Ok in preview but when I publish it to my local ServBay instance, I also get just the single line:
No item found
What is odd is there is nothing else shown on the page, looking at the browser source. 
It seems like the CMS has got / detected an error and cancels the whole page with no further info available?
Thanks for the report, @ben will dig further into this one and find out what’s going on!
the reason is because you’re linking the single item to a folder — essentially making this a “Collection Item”.
tl;dr: Link the Item component to the single basic.md file instead of the “about” folder.
When you link an Item to a folder, it requires there to be a URL parameter of item={slug} so the CMS knows when item you want to display.
It works when you preview the site locally because the CMS automatically fetches the first item in the folder, if the item={slug} isn’t set in the URL. We do this so you can preview your site locally without errors like “Cannot find item NULL".
When you publish this page, the CMS will attempt to find the Item in the collection folder that you’ve linked it to in Elements (in your case the “about” folder) — because there is no item=basic in the URL, it cannot find the item. This is why you are seeing “No item found”.
I’ve tried to explain this further in the video below, but do let me know if it still doesn’t make sense 
