C44 CRC check failure on primary bus
If you unable to resolve the issue, log in to http://myUR.universal-robots.com and create a new case.
C44A0 Base
C44A1 Shoulder
C44A2 Elbow
C44A3 Wrist 1
C44A4 Wrist 2
C44A5 Wrist 3
C44A6 Tool
C44A80 CRC Check failure on primary bus.
Most likely an interference on the communication bus.