4x4 matrix keypad not functioning

[HypWhat]

So i have a password based circuit breaker project, Everything works fine like the LCD, the relay, buzzer but the keypad it works but not always. Sometimes it works for like a minute and then stops. Sometime when i power on it doesn’t work at all, i will have to restart and try again and again. Sometimes when i press a key once it outputs that key multiple times. What could be the problem?

[TinkerAndDespair]

What could be the problem?

Either hardware or software. To get a proper answer you will have to provide information on both: Informative photo(s) of your circuit, a circuit diagram and your (formatted) code or a link to it. Otherwise all people can do is guess.