In our case we are firing the soap messages to a fixed URL that hosts the web service. This is giving "INTERNAL SERVER ERROR 500K" in the log file and "VU Crashed in middleware ," in output pane and validation of script is getting failed.
Can anyboby help me in this regard. What may be the possible reason of this error.How to debug it??
If you are sending large quantities of messages very quickly, it is possible that when the server fails to respond (500 server error), that the users trip all over themselves trying to send messages, and the whole process space collapses.
Three things to try: If you're using data, ensure that all of the data items you have work on their own - that is, start one user and run through the datapool to make sure there are no bad records.
Two, try running the virtual users in process mode - they tend to be a little more isolated from one another that way, so maybe only one user will die when the server fails to respond.
Three, look through the server logs to see what the server thought of the error - generally the answer will be found here, but can be pretty hard to locate.
Hope that helps! If the problem persists, contact technical support.
Bryan is absolutely correct in his approach. It should be noted that the 500 error is a server side error, and not a client side problem, and tends to require debugging/modifications to the server side configurations of the web server software. The server logs as viewed through the eyes of your server admins would be the best bet to find and resolve the issue.