Unable to publish a ClickOnce Application
Error 1 Cannot publish because a project failed to build.
Error 2 An error occurred while signing: Failed to sign bin\Debug\app.publish\\setup.exe. SignTool Error: The signer's certificate is not valid for signing.
SignTool Error: An error occurred while attempting to sign: bin\Debug\app
The test certificate used to sign the manifest files has expired.
Hence we created a new test certificate and published the application using that certificate successfully.
Please refer the below links for more information on creating a test certificate.
Content By : Pooja Kalita