Using a Load Balancer and getting an unable to log into server B 404 error

Issue

Using a Load Balancer, why am I getting an unable to log into server B 404 error?  Both servers are configured identically.

Server "A" works while server "B" did not.

Cause

The Load Balancer was incorrectly set up.

Solution

Got a HAR file for the working server "A" and the non-working server "B".  A comparison of the HAR files showed that server "B" had the following:

1. A mixture of URLs to both server "A" and "B".   The Load Balancer needed to be changed so all URLs were for server "B".
2. The URLs for server "A" was http, whereas server "B" was set to https.  Changing to http resolved the issue.

Level of Complexity 

Moderate

Applies to  

References

How to collect a HAR trace file - Kofax