Its not a warning, its the final error message. Please note that once task is submitted you can not change the result (passed or failed) so make sure you are sure about your solution before submitting the task.
ok sure, will take here after. I have a query, do you mean to say whatever I did/corrected after that error is not saved or considered to close the task successfully right …?
As We get 5 mins to perform the correction, I thought that it would be considered as done. 
Yes, it will not change the final status of the submitted task. Those 5 minutes are just to check/understand what was the mistake in case failure.