If your succulent cutting isn't rooting it could be because it didn't callous over completely or you're overwatering your new plant. Another reason why your succulent cutting might not be rooting is poor-quality soil. If your potting soil or mix lacks all the required nutrients or is of an incorrect type, the roots may not develop. Lastly, make sure the medium you are growing the succulent in facilitates proper drainage, so excess water does not retain in the medium.