Stata synth_runner error message

Hi, I encountered this error message when I use Stata and run the synth_runner command. Could anyone please help? I could not figure out what caused the error. I do not have missing values for the dependent variable, but it reports missing. The panelvar is each county, and the treatment is at state level. When I run synth using this data, it has no problem. I also attached the dataset that I used. Your help would be greatly appreciated. Michael . qui set matsize 2000 . qui use test2, clear . qui gen D = 0 . qui replace D = 1 if (state_id == "CO" ) & (year >= 2013) . qui replace D = 1 if (state_id == "AR" ) & (year >= 2015) . qui replace D = 1 if (state_id == "AZ" ) & (year >= 2015) . tsset fips year panel variable: fips (strongly balanced) time variable: year, 2008 to 2017 delta: 1 unit . synth_runner y x1 x2 x3 x4 , d(D) trends Estimating the treatment effects Error estimating treatment effect for unit 8001 Re-running last -synth- command with output/errors un-captured ------------------------------------------------------------------------------------------------------------------ Synthetic Control Method for Comparative Case Studies ------------------------------------------------------------------------------------------------------------------ First Step: Data Setup ------------------------------------------------------------------------------------------------------------------ control units: for 3 of out 200 units outcome variable y is missing in 2008 pre-intervention MSPE period - check m > speperiod() invalid syntax r(198); end of do-file r(198); .