I am encountering a odd issue. we have 3 servers which are load balanced by F5. Using Performance layer 4/Fast L4 profile.
When the end user access the URL, the webpage opens fine and when they have to perform longer operations(like querying or retrieving something which lasts longer, a minute or two), suddenly they are returned with "internal server error".
But, when they access the server directly and perform the same operation, it works fine. This happens only with F5. So i understood something needs to be tweaked in the F5 but i am not sure what.
Since website is opening with success via F5 VS, it seems there is no connectivity issue between Client--F5--Server. However you can change the VS type as Standard and check if issue persist. FastL4 profile can cause issue with iRules and http profiles which are trying to manipulate L7 http data.