Sometimes I run into issues with my macOS wireless. Yes I know that most problems come by myself by wrong configurations. But here now a very handy short way which helped me already many times. Attention! You will need it to rejoin the network.

# change directory
$ cd /Library/Preferences/SystemConfiguration/

# list files (optional)
$ ls -la

# delete specific files
$ rm com.apple.airport.preferences.plist com.apple.network.identification.plist NetworkInterfaces.plist preferences.plist

Finally reboot the system and join your network. This forces the macOS to create all preference files again.