I have a script home-->login-->logout
with same users test data script successful sometimes and fail some times.
in failure case it is not showing any wrong user credentials but going to default page automatically when try to login.
It could be some other parameter like session info that is becoming invalid, so look at the failing request details, or somewhere before. Also, check the box for "Emulate new browser" when selecting the Actions container. It is on the right side for the checkbox.
This issue has been solved by the Neotys technical support. The issue was related to a recorded cookie. The name of that cookie was dynamic and so when replaying the script, the server sends a different cookie name.
As a consequence, both cookies were sent instead of only the new one. The solution was to remove the recorded cookies since they are only useful for troubleshooting.