Hello this is my first post! I am using YTS data from the CDC ill put a link down below. I am currently trying to run fixed effect regression on my data but when I command: xtset Stateid YEAR I get the error r(451). from what I can tell its saying every time the state and year are the same its a repeated time value even though the data throughout the row is different. If someone knows the problem or how I can work around it would be great!

if you need any more details please let me know. Thank you!

What I am trying to do with stata
xtset Stateid YEAR
xtreg Data_Value policy Gender Education i.YEAR, fe robust

policy = LocationAbbr: "CA" "HI" when YEAR > 2015

preview of data as I currently have it
Array

Orginal Dataset:
https://chronicdata.cdc.gov/Survey-D...Data/4juz-x2tp