No, it’s not okay to have mold on your scoby or on the top of your kombucha liquid. You’ll nee to discard it and start again. Make sure that everything is sterile when you start your kombucha. It is possible to restore the scoby by removing any mold and placing distilled vinegar in place of kombucha liquid when you restart a batch. Often times mold is the result of either not enough sugar, your kombucha not being kept in a warm room or including extras in your kombucha which encourage mold growth. Also, don’t let your scoby dry out, it should be kept in a moist environment of liquid. It’s important that your kombucha is sealed with the cover cloth, which will allow breathing but should prevent mold spores from entering.
Also, it’s a good idea to separate a part of your culture at the beginning and refrigerate it, so you have a backup in case something happens to the master batch.
If your scoby is dead (it’s an organism) it will mold. If you scoby is too cold (below 32f) or freezes it will mold.