The computer you're running it on needs to have the .Net framework installed.
If you're not using IE, you need to install the ClickOnce extension. They're available for Chrome, Safari and Firefox.
https://chrome.google.com/webstore/detail/eeifaoomkminpbeebjdmdojbhmagnncl[
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If you've published it to an IIS server, you need ensure .application is registered as a MIME type.
If you're using visual studio development server, this uses the 127.0.0.1 loop back and can't be accessed by any other computer.
You also need to make sure the installation path associated with the ClickOnce manifest matches the URL being used to load the application.
So a publishing folder of http://localhost/MyClickOnceApp is no good.
As the client machine will download the manifest and then try and get the rest of the files from that address. Which won't work as they will unlikely have IIS running and less likely to have the same click once available at the same location in it's local IIS.
You need to change the publish path to http://ComputerName/MyClickOnceApp