Manifest may not be valid or the file could not be opened.
I was able to solve my issue by removing the signing of the manifest.
If you right-click your project and go to properties then to the Signing Tab; uncheck the Sign the ClickOnce manifests and Sign the assembly.
I'm not sure what this does in terms of security but my app installed after I removed these options.
I had the same issue and it was just the machine didn't have the appropriate .Net version.
I found the reason. It was MIME type issue in server setting.
So, please add .htaccess file in FTP root directory.
And write this in it.
AddType application/microsoftpatch .mspAddType application/microsoftupdate .msu AddType application/x-ms-application .application AddType application/x-ms-application .manifest AddType application/octet stream .deploy AddType application/x-ms-vsto .vstoIt works perfectly for me.