Provisioning system via PXE-Less discovery fails with error "Proxy error HTTP 500 (500 Internal Server Error): Cannot download kernel"

Issue

• Provisioning system via PXE-Less discovery fails with error Proxy error HTTP 500 (500 Internal Server Error): Cannot download kernel
• Unable to kexec a system which is discovered via PXE-Less discovery method fails with following errors captured in production.log and proxy.log

==> /var/log/foreman-proxy/proxy.log <==
E, [2017-07-13T15:03:53.197393 #10279] ERROR -- : Proxy error HTTP 500 (500 Internal Server Error): Cannot download kernel: 4)
192.168.100.3 - - [13/Jul/2017 15:03:53] "PUT /discovery/192.168.100.10/power/kexec HTTP/1.1" 500 76 1.8950

==> /var/log/foreman/production.log <==
2017-07-13 15:03:53 [D] # => 500 InternalServerError | application/json 76 bytes

2017-07-13 15:03:53 [W] Unable to kexec mac00062f54b39f:
2017-07-13 15:03:53 [W] /opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/abstract_response.rb:48:in `return!'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:230:in `process_result'
/opt/rh/ruby193/root/usr/share/gems/gems/rbovirt-0.0.37/lib/restclient_ext/request.rb:50:in `block in transmit'
/opt/rh/ruby193/root/usr/share/ruby/net/http.rb:746:in `start'
/opt/rh/ruby193/root/usr/share/gems/gems/rbovirt-0.0.37/lib/restclient_ext/request.rb:44:in `transmit'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:64:in `execute'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:33:in `execute'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/resource.rb:76:in `put'
/opt/rh/ruby193/root/usr/share/gems/gems/foreman_discovery-2.0.0.23/app/services/foreman_discovery/node_api/node_resource.rb:102:in `put'