question about time fixed effects model

Dear all,

I am running an OLS model in Stata and one of the explanatory variables is the interaction between another explanatory variable and time dummies. My question is: if I want to run an OLS with time fixed effects is it enough to run the usual OLS with that interaction variable (because one of the variables already has time dummies included in it) or do I have necessarily to add i.time for obtaining a time fixed effects regression?

The problem is that if I add i.time, the variables I am interested in become statistically insignificant…

Thank you very much for your help,