Many times I get this question. (The user didn’t change the WiFi configuration at home)
Usually the problem is caused by resent OS update.
Many times to fix it is to reset the NVRAM (here is more info about NVRAM: https://support.apple.com/en-us/HT204063)
- Shutdown your computer
- press the power button and hold these four keys until your computer makes the chaim sound twice.
3. let the computer finish booting and test the WiFi connection