What makes a main relay go out.

I just replace my timing belt and tentioner, car was sitting for a week, had brand new main relay in it and now wont start

i know its the main relay because i can hear it clicking and the lights on the left side of the cluster wont come on, check engine, battery, and oil i believe.

What is making my main relay go out. any ideas please help.

oh and if you have an extra one, i need one asap