If one of the attachments isn’t connecting to the massager, you should check the FitRx Mini Pro Massage Gun’s massage stem. Ensure that it is not damaged or physically deformed in any way, as this will prevent the attachments from securely attaching to it.   You should always keep the massage gun and all its included components in the included carry case when they are not being used. The massager and its attachments may be damaged if they are not in the case. If there are no visible issues with the massage stem or the attachments, though, then another issue may be present with your product. Contact Customer Service for more information.