Error Messages

The following table lists messages that can appear in system log files. This list is not exhaustive; it simply describes common warning messages that can occur and which might require your attention.

Fatal Process Messages

Accept port is not between 1 and 65535. Please check configuration

The port specified in records.yaml that accepts incoming HTTP requests is not valid.

Self loop is detected in parent proxy configuration

The name and port of the parent proxy match that of Traffic Server. This creates a loop when Traffic Server attempts to send the request to the parent proxy.

Process Warnings

<Logfile> error: error_number

Generic logging error.

Connect by disallowed client <IP address>, closing

The specified client is not allowed to connect to Traffic Server; the client IP address is not listed in the ip_allow.yaml file.

Could not rename log <filename> to <rolled filename>

System error when renaming log file during roll.

Log format symbol <symbol name> not found

Custom log format references a field symbol that does not exist. Refer to Formatting Log Files.

Missing field for field marker

Error reading a log buffer.

Unable to open log file <filename>, errno=<error number>

Cannot open the log file.

Error accessing disk <disk name>

Traffic Server might have a cache read problem. You might need to replace the disk.

Too many errors accessing disk <disk name>: declaring disk bad

Traffic Server is not using the cache disk because it encountered too many errors. The disk might be corrupt and might have to be replaced.

No cache disks specified in storage.config file: cache disabled

The Traffic Server storage.config file does not list any cache disks; Traffic Server is running in proxy-only mode. You must add the disks you want to use for the cache to storage.config.

HTML Messages Sent to Clients

Traffic Server returns detailed error messages to client browsers when there are problems with the HTTP transactions requested by the browser. These Traffic Server response messages correspond to standard HTTP response codes, but provide more information. A list of the more frequently encountered HTTP response codes is provided in HTTP Status Codes.

The error messages can be customized. The actual response is generated from a template. These templates are stored in files which means the errors responses can be customized by modifying these files. The default directory for the template files is PREFIX/body_factory/default but this can be changed by the configuration variable proxy.config.body_factory.template_sets_dir. All files in this directory are added to a lookup table which is consulted when the error message is generated. The name used for lookup is by default that listed in the following table. It can be overridden by proxy.config.body_factory.template_base which, if set, is a string that is prepended to the search name along with an underscore. For example, if the default lookup name is cache#read_error then by default the response will be generated from the template in the file named cache#read_error. If the template base name were set to apache then the lookup would look for a file named apache_cache#read_error in the template table. This can be used to switch out error message sets or, because this variable is overridable, to select an error message set based on data in the transaction. In addition the suffix _default has a special meaning. If there is a file with the base name and that suffix it is used as the default error page for the base set, instead of falling back to the global (built in) default page in the case where there is not a file that matches the specific error. In the example case, if the file apache_default exists it would be used instead of cache#read_error if there is no apache_cache#read_error.

The text for an error message is processed as if it were a Log Fields which enables customization by values present in the transaction for which the error occurred.

The following table lists the hard-coded Traffic Server HTTP messages, with corresponding HTTP response codes and customizable files.

Access Denied

403 You are not allowed to access the document at location URL. access#denied

Cache Read Error

500 Error reading from cache; please retry request. cache#read_error

Connection Timed Out

504 Too much time has elapsed since the server has sent data. timeout#inactivity

Content Length Required

411 Could not process this request because Content-Length was not specified. request#no_content_length

Cycle Detected

400 Your request is prohibited because it would cause an HTTP proxy cycle. request#cycle_detected


403 <port number> is not an allowed port for SSL connections (you have made a request for a secure SSL connection to a forbidden port number). access#ssl_forbidden

Host Header Required

400 An attempt was made to transparently proxy your request, but this attempt failed because your browser did not send an HTTP Host header. Manually configure your browser to use http://<proxy name>:<proxy port> as the HTTP proxy. Alternatively, end users can upgrade to a browser that supports the HTTP Host header field. interception#no_host

Host Header Required

400 Because your browser did not send a Host HTTP header field, the virtual host being requested could not be determined. To access the website correctly, you must upgrade to a browser that supports the HTTP Host header field. request#no_host

HTTP Version Not Supported

505 The origin server <server name> is using an unsupported version of the HTTP protocol. response#bad_version

Invalid Content Length

400 Could not process this request because the specified Content-Length was invalid (less than 0).. request#invalid_content_length

Invalid HTTP Request

400 Could not process this <client request> HTTP method request for URL. request#syntax_error

Invalid HTTP Response

502 The host <server name> did not return the document URL correctly. response#bad_response

Malformed Server Response

502 The host <server name> did not return the document URL correctly. response#bad_response

Malformed Server Response Status

502 The host <server name> did not return the document URL correctly. response#bad_response

Maximum Transaction Time exceeded

504 Too much time has elapsed while transmitting document URL. timeout#activity

No Response Header From Server

502 The host <server name> did not return the document URL correctly. response#bad_response

Not Cached

504 This document was not available in the cache, and you (the client) only accept cached copies. cache#not_in_cache

Not Found on Accelerator

404 The request for URL on host <server name> was not found. Check the location and try again. urlrouting#no_mapping


502 The host <hostname> did not return the document URL correctly. response#bad_response

Proxy Authentication Required

407 Please log in with username and password. access#proxy_auth_required

Server Hangup

502 The server <hostname> closed the connection before the transaction was completed. connect#hangup

Temporarily Moved

302 The document you requested, URL, has moved to a new location. The new location is <new URL>. redirect#moved_temporarily

Transcoding Not Available

406 Unable to provide the document URL in the format requested by your browser. transcoding#unsupported

Tunnel Connection Failed

502 Could not connect to the server <hostname>. connect#failed_connect

Unknown Error

502 The host <hostname> did not return the document URL correctly. response#bad_response

Unknown Host

500 Unable to locate the server named <hostname>; the server does not have a DNS entry. Perhaps there is a misspelling in the server name or the server no longer exists; double-check the name and try again. connect#dns_failed

Unsupported URL Scheme

400 Cannot perform your request for the document URL because the protocol scheme is unknown. request#scheme_unsupported

URI Too Long

414 Could not process this request because the request uri was too long .. request#uri_len_too_long