RMX was added to DMA but RMX status remains in an out of service status.

Go to DMA home page->network ->MCU and clicked add MCU to input the NBG RMX2000 management IP, login user name, pwd etc. After we completed the form, we found MCU out of service. Tried added again, and also tried reinstalled DMA system, same issue. Multiple RMX added to this DMA would show same issue.