Hi oinamors,
Welcome to the Community.
I would suggest you to perform a system restore for the date the wifi was working properly on the mobile phone.
For system restore click the link mentioned below:
Note: System Restore will remove all the applications installed after the restore point.
Also, let me know the following details:
1 Laptop Model
2 Operating System Installed
3 Are you using any 3rd part software to create hotspot?
Thanks & Regards
Manshu S
#iworkfordell