I have fitted a regression model on my mean-centered variables. Every regression coefficient is significantly different from zero but the interaction terms created by multiplying the independent variables together are not.

My queries are:

1. What could be the possible cause for this weird pattern?
2. what diagnostics and remedial actions could be taken to correct this?

**Update**

Actually one of my independent variable in moderator and so the Interaction term that is calculated by multiplying centered-moderator with centered-independent variable should come out as significant but it is not.
Now what diagnostic and remedial actions are advised here?