Did you allow the car to reset? Are you getting an SOS warning on the dash display or iDrive? If you get the SOS your optical connection is not correct. If it is connected properly, do you have a 12v out from the blue remote wire?
Mobridge DA2 > JBL MS-8 > ARC XDi 600/4 > JBL Gti 408 Mids & Vifa OT19 Tweeters; PG Ti2 1600.5 > Morel HCW-10 & IDMax 15