=IF(AND formula returning "invalid Operation" error


I have several check box columns.    When all are checked, I want to turn on a flag in another cell. 

I first tried testing two of five check box fields and Smartsheet returns "invalid operation"

=IF(AND(COI:COI = "1", EFT:EFT = "1"), "1")

What am I doing wrong?


Help Article Resources

Want to practice working with formulas directly in Smartsheet?

Check out the Formula Handbook template!