Hi, I'm new here (and new to stata/statistical analysis) i need help with a count model with data panel.

i have some panel from a count of a financial transactions per transactional channel of 500 customers of a financial institution , i try to evaluate the impact of diferent socioeconomics variebles in the demand of each channel.
As my dataset contains many many 0 (there are no transactions in a channel i for a client j), I understood that maybe a poisson panel model were appropriate in my case, to account for 0 and overdispersion
So I tried to estimate
xtpoisson txn_canal multicanal genero edad activos pasivos tarjetas
i try to estimate marginals effects but i can't use " margins"
Why my independent variables is "not found in the list of covariates"
what can i do?
Thanks you for your help!!