Currently if any error happens when signing a certificate request, Foreman will throw a 500 error page.

See the following example for a error of a client sending a broken cert request (incompatible digest algorithm):

ERF12-9815 [ProxyAPI::ProxyException]: Unable to sign PuppetCA certificate for samplehost ([RestClient::NotAcceptable]: 406 Not Acceptable) for proxy https://mydomain:9090/puppet/ca

We can handle this through an alert and return back to the smart proxy puppetCA index page.