This warning means that your Wi-Fi connection is either using a very simple or easy-to-guess password -- or the default one -- meaning you may be at risk. Wi-Fi Inspector also checks to see if your router's admin panel is using the default password; if so, make sure you change that as well.
Means your password for the router is to easy to guess. Try changing the password using numbers with both upper and lower case. Also symboles if allowed. Try atleast 1 upper case with a few lower case with one symbole. Example: 18@Shakeel1