# Error HTTP

**URL:** <https://community.a10networks.com/t/error-http/845>\
**Category:** ADC - Application Delivery\
**Created:** [May 13, 2024, 3:49pm UTC](https://community.a10networks.com/t/error-http/845 "2024-05-13T15:49:43Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![NorCal](https://avatars.discourse-cdn.com/v4/letter/n/c37758/32.png) [@NorCal](https://community.a10networks.com/u/NorCal)\
**Post date:** [May 13, 2024, 9:11pm UTC](https://community.a10networks.com/t/error-http/845/1 "2024-05-13T21:11:31Z")

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Alfredo,

I realize this is in Azure, but would it be possible to use a client to send a request directly to the backend server (circumvent the load balancer) and see if you get the same HTTP 431 error? This would help narrow down if the load balancer is at fault, or the server is at fault.

How big are the headers you are sending to the VIP on the load balancer?

Thank you.

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**Author:** ![mdunn](https://avatars.discourse-cdn.com/v4/letter/m/87869e/32.png) [@mdunn](https://community.a10networks.com/u/mdunn)\
**Post date:** [May 16, 2024, 8:28pm UTC](https://community.a10networks.com/t/error-http/845/2 "2024-05-16T20:28:46Z")

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The maximum HTTP header size should be 64KB. If the header length is exceeded, a Warning log should generate similar to “Warning [ACOS]:HTTP header (len=108) “” is too long”