After a trip using the autopilot with no issues last week...now I've got a red "err" beside the AP digits on the d10 efis. I'm using the AP74 for controlling the autopilot with both pitch and roll servos on my RV6. After checking the DSAB network it showed it wasn't configured...so I reset it to recognize the components on the DSAB. It now shows that the roll servo isn't detected within the network. I next tried to test the system using the only detected servo ...which is the pitch servo. The EFIS screen shows autopilot commands for pitch,but nothing is happening. On initial power up the AP74 lights all are operational. Autopilot is inop in either pitch or roll while in flight..... The CWS autopilot disconnect switch is good. Circuit breaker is fine and never tripped.....any ideas? :-/