Hello, I have a simple backend: backend lms_be option httpchk HEAD / HTTP/1.1\r\nHost:\ lms.FQDN option accept-invalid-http-response server lms_be1 10.11.106:80 check when my client do a post request: POST /bccr/upload/IsApiFilter/UploadExt.dll??508&template8.asp HTTP/1.1 content-length: 1950 …

That’s not a valid response. There is not HTTP header at all.

Issue a show errors on the admin socket and provide the output: [image] HAProxy version 2.2.0 - Management Guide

below the error: [08/Oct/2020:16:42:54.054] backend lms_be (#113): invalid response frontend http-https (#3), server lms_be1 (#1), event #0, src 192.168.92.48:47156 buffer starts at 0 (including 0 out), 13769 free, len 2615, wraps at 16336, error at position 0 H1 connection flags 0x00000000, H1…

what a fool, I didn’t pay attention to the headers! :sleeping: meanwhile I investigate, I do not mark the problem as solved just to understand why the backend sends me that answer. thnx a lot.

The problem is in a DLL IsApiFilter, using the browser directly it works I guess because it doesn’t respect the standards :slight_smile: thanx again.

502 Bad Gateway The server returned an invalid or incomplete response

Help!

lukastribus October 9, 2020, 10:16am 2

Issue a show errors on the admin socket and provide the output:

Topic		Replies	Views
502 Bad Gateway, response from upstream server is blocked by haproxy Help!	1	1079	May 31, 2022
"502 Bad Gateway Help!	0	322	January 19, 2022
Everything working, but one page returns 502 Help!	7	5516	September 19, 2018
502 Bad Gateway invalid response Help!	2	412	June 6, 2023
Troubleshooting 502 Bad Gateway Help!	3	1910	November 9, 2018

502 Bad Gateway The server returned an invalid or incomplete response

Related topics