Hello,
Try to perform Network Reset and then re-enable Mobile hotspot:
- Open Settings app, click Network & Internet > Status > Network reset link.
- Now click on Reset button on next screen.
- In confirmation prompt appearing next, click Yes.
Let us know if this helps!
Reference: https://www.kapilarya.com/how-to-reset-network-settings-to-default-in-windows-10
Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.