Hi guys, i'm trying to run a muilti-fixed effects regression using reghdfe
when i type my code:

reghdfe log_tobin DiD1 $xlist if fisc_year>=2014 & fisc_year<=2017, a( co_code fisc_year sic_code) vce(robust)

I get an error saying "class FixedEffects Undefined"

How would i go about solving this issue?