Thanks for posting your concern here, Dymphna Rowan.
In this case, please try to run Surface Diagnostic Toolkit and check for Windows Update. Also, check if MAC address filtering is enabled. Give these methods a try:
- On your Surface, type cmd in the search box, and select Command Prompt (run as admin).
- Then in the prompt, type ipconfig/all and hit Enter.
- Find the Physical address. It will be the MAC address for your Surface. Take note of it.
- Turn off MAC filtering temporarily to see if that is preventing your Surface from connecting to your iPhone hotspot.
- Add the MAC address of your Surface to your iPhone’s authorized list. Then, test it.
Feel free to respond on this thread to let us know how it goes.