1. Open Control Panel and navigate to Network & Sharing Center.
2. Check Access Type for your hotspot as shown in the below figure.
3. If you have Internet as Access type, then your firewall or Antivitrus must be blocking mHotspot.
4. Add an exception to mHotspot in Windows firewall & Antivirus Firewall.
5. If you have No network access, stop the hotspot.
6. Go to this article and follow the complete steps.
7. If the problem remains, after following the above procedure install the hotfix provided by Microsoft from here. If the problem remains even after hotfix, read this post on how to manually enable sharing.