6 independent relays

I used an Arduino nano to control 6 lights using 6 independent relay modules , but mysteriously one of the relay stopped working. can anyone help me why this happened

We probably can help.

Do you think you should present a bit more information ?

Just for helpers pleasure, code in codetags and wiring diagram containing logic and pwr lines.

Could the relay be broken?

Swap that relay with another one to check.