VBA IF formula not working getting Run-time Error '1004"

Working on the following VBA IF formula. Unfortunately not working getting Run-time Error '1004". can anyone help me? what I am doing wrong?.

Range("AC3").Formula = "=IF(T3=""USER1"",Encrypt(AC3,FALSE),IF(T3=""USER2"",Encrypt(AC3,FALSE),IF(T3=""USER3"",Encrypt(AC3,FALSE),IF(T3="USER4"",Encrypt(AC3,FALSE),IF(T3=""USER5"",Encrypt(AC3,FALSE),IF(T3=""USER6"",Encrypt(AC3,FALSE),K3)))))))