{"record":{"id":"59f9bbd20ef98eab","repo":"caddyserver/caddy","slug":"unrecognized-pem-block-type-s","errorCode":null,"errorMessage":"unrecognized PEM block type: %s","messagePattern":"unrecognized PEM block type: (.+?)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"modules/caddytls/folderloader.go","lineNumber":151,"sourceCode":"\t\t\t\tderBlock, bundle = pem.Decode(bundle)\n\t\t\t\tif derBlock == nil || derBlock.Type != \"EC PRIVATE KEY\" {\n\t\t\t\t\treturn tls.Certificate{}, fmt.Errorf(\"expected elliptic private key to immediately follow EC parameters\")\n\t\t\t\t}\n\t\t\t\tif err := pem.Encode(keyBuilder, derBlock); err != nil {\n\t\t\t\t\treturn tls.Certificate{}, err\n\t\t\t\t}\n\t\t\t\tfoundKey = true\n\t\t\t}\n\t\t} else if derBlock.Type == \"PRIVATE KEY\" || strings.HasSuffix(derBlock.Type, \" PRIVATE KEY\") {\n\t\t\t// RSA key\n\t\t\tif !foundKey {\n\t\t\t\tif err := pem.Encode(keyBuilder, derBlock); err != nil {\n\t\t\t\t\treturn tls.Certificate{}, err\n\t\t\t\t}\n\t\t\t\tfoundKey = true\n\t\t\t}\n\t\t} else {\n\t\t\treturn tls.Certificate{}, fmt.Errorf(\"unrecognized PEM block type: %s\", derBlock.Type)\n\t\t}\n\t}\n\n\tcertPEMBytes, keyPEMBytes := certBuilder.Bytes(), keyBuilder.Bytes()\n\tif len(certPEMBytes) == 0 {\n\t\treturn tls.Certificate{}, fmt.Errorf(\"failed to parse PEM data\")\n\t}\n\tif len(keyPEMBytes) == 0 {\n\t\treturn tls.Certificate{}, fmt.Errorf(\"no private key block found\")\n\t}\n\n\t// if the start of the key file looks like an encrypted private key,\n\t// reject it with a helpful error message\n\tif strings.HasPrefix(string(keyPEMBytes[:40]), \"ENCRYPTED\") {\n\t\treturn tls.Certificate{}, fmt.Errorf(\"encrypted private keys are not supported; please decrypt the key first\")\n\t}\n\n\tcert, err := tls.X509KeyPair(certPEMBytes, keyPEMBytes)","sourceCodeStart":133,"sourceCodeEnd":169,"githubUrl":"https://github.com/caddyserver/caddy/blob/50e54ee279aa1e504fe218ca49ab6ae16c100410/modules/caddytls/folderloader.go#L133-L169","documentation":"Error \"unrecognized PEM block type: %s\" thrown in caddyserver/caddy.","triggerScenarios":"Thrown at modules/caddytls/folderloader.go:151 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Remove or fix PEM blocks with unrecognized types in the key file; only certificate and private key blocks are supported."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"50e54ee279aa1e504fe218ca49ab6ae16c100410","analyzedAt":"2026-08-15T09:20:21.641Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}