I have both 941 and 943 employees. I as able to successfully e-file my W-2's for the 941 employees however I received notice that the 943 e-file was rejected by the SSA as a "duplicate". I double checked and there are no duplicate employees in the filings and I clearly marked one W-3 as 941 and the other as 943. Do I need to just mail the rejected filing to SSA? Has anyone else encountered this?