Hello, I have Stata 15.1 installed and today reghdfe stopped working and gives me the following error 'class FixedEffects undefined'. I used the same data yesterday and it worked without issue. I have version 5.6.8 of reghdfe and tried to reinstall today. I am really not sure what the issue is as I get the same error even if I use the example from the help file:
sysuse auto
reghdfe price weight length, absorb(rep78)

Any thoughts on why this would stop executing?

Thank you