Kenneth -
Which board are you using? Are you using a stage box? What is your configuration? Which version firmware?
I had this problem with my SL16 S3 connected to my 32R set up in stage box mode, with the monitors hooked to the 32R. It turned out that I had configured the digital routing incorrectly. The Auxes need to be set to Analog not Networked. Once I changed that, everything worked.