Hi SBpDPc;
There are four possibilities:
1)Normal dreams can have information too. Look for signs in your normal dreams.
2)You may need to try it more than once. I'd suggest you to keep trying in this case.
3)You may not need to sleep to get the info you seek. Thus you can get the info while you're awake.
4)The information you seek may be blocked by your higher self to protect you from it. This is unlikely and should be considered only if you try many times and fail all the time. It can also be revealed automatically in a later point of your life, when you're ready for it.