[error] 19168#0: *13447 upstream prematurely closed connection while reading response header from upstream, client: 203.82.37.90, server: test-spcommutyble.com, request: "POST /pricing/272 HTTP/1.1", upstream: "passenger:/tmp/passenger.1.0.19148/generation-0/request:", host: "test-sp.commutyble.com", referrer: "http://test-sp.commutyble.com/pricing"