Is anyone here using a dpp 44 with their 921. I am a retailer who has a customer attempting to do this and he is getting 2 error messages. first error 623 the error 613. the 921 is on port one of the switch and a 508 is on port 2 of the 44 and works fine. the power inverter is on port one between the switch and the separator. The 921 is running L186. Anyone out there who can help please I'd greatly appriciate it.