Here are a few things you might check:
Troubleshooting Issues with MSG waiting lamps across CCIS (2000 IPS and SV8300)
Main Site Voice Mail -
UM8000 - supported on SV8300
UM4730, UM8500, AD120 - supported on 2000 IPS and SV8300, must use MCI integration for CCIS
UCB - supported on 2000 IPS and SV8300, must use MCI integration for CCIS
Other manufacturer VM - supported on 2000 IPS and SV8300, must use Message Center Interface (MCI) integration for CCIS
Main Site PBX -
2400 or SV8500 using IP CCIS (Peer-to-Peer) or IP Trunking -
Ø Make sure the Point Code of the Remote 2000 IPS or SV8300 exists in ACIC1
2000 IPS or SV8300 -
Ø Make sure CMA8 (IPS) or CMA8x (SV8300) is correct for the far end Point Code
Ø Make sure CCH 0 is programmed. If CMA700>0 (IPS) or CMA700>00 (SV8300) is NONE then no MSG lamps will be sent across to the Remote Site. As a workaround if not using CCH 0 (00), program a phantom trunk in CMA700>0 (00).
Ø Make sure the station in the Remote Site does not exist in the Main Site. Although Least Cost Routing (LCR) for station number is set to go across CCIS the lamp packet will never be sent across CCIS if the station exists in the Main Site. If using Busy Lamp Field (BLF) over CCIS feature, make sure all programming is correct.