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MuleSoft Unable to Send Encoded Special Characters in URL to DLB or "HTTP 505 - HTTP Version Not Supported" Sending Request via DLB

Julkaisupäivä: May 7, 2026
Tehtävä

When sending request to an API Application via a Dedicated Load Balancer (DLB) with MuleSoft, you may get the following error:

 

HTTP/1.1 505 HTTP Version Not Supported

A sample curl request that can cause the "505 HTTP Version Not Supported" error as demonstrated below, is caused by a white space in the url "/api/test service":
curl -kv -X GET 'https://lb-test-prod.lb.anypointdns.net/api/test%20service/test

This issue is related to a 3rd party limitation (nginix) used in Dedicated Load Balancers to handle the whitespace, encoded whitespace (%20), and number # (%23) in the URL.

Vaiheet

Our MuleSoft Engineering Team has confirmed with nginix that currently it only supports the %20 and %23 characters. Other special characters are currently not supported.
 
Please refer to the following options to address the issue:

1. If you are using the "%20" space character and/or "%23" characters in the URL, please ensure that in the DLB configuration the Keep URL encoding option is selected.

2. Prevent using whitespace or any other special characters in a URL. Instead, use + characters.

Knowledge-artikkelin numero

001116355

 
Ladataan
Salesforce Help | Article