Insufficient observations for imputation

[Adrienne Wold]

Hi,
I am trying to impute values for a single variable in a 3year panel, though the variable I am trying to impute is time-invariant. I am thus trying to impute values at the group level, where the group is the id units of the panel (media_outlet). After running the following code:

mi set wide
mi register imputed subscribers
mi impute regress subscribers, by(media_outlet) add(5) rseed(12345)

I receive the error code insufficient observations for numerous outlets and the imputation does not take place. Is there a way to simply pass through these observations s/t values are still imputed for those observations that do have sufficient observations?

Thank you.