First of all, remember that Chamilo 1.9 is not released for production and is for testing purpose only.
Could you give a bit more of information on how you performed the test (using which account and so on)?
In the meantime, you can delete all attempts (but this means ALL attempts, for all students).
You therefore can give a go for another test.
What could happen is that the connection is lost and the platform may consider the first attempt as complete, you then do the "real" test up to the end and the platform sees 2 attempts.
For this, just have a look on the statistics of the course (here of your test) to ensure the number of tries.