Please help to explain HDX Disconnect reasons,Thanks

[drifter]

Local ID and Disconnect Reason

The call has ended.

The call has ended.; Local user initiated hangup.

Failed Attempt; "The far end system is capable of accepting the call, but the call was rejected for an unknown reason. Contact your network administrator for assistance.; Rolling Over."

Failed Attempt; "Your call could not be completed because the call was routed through an intermediate network that does not service the far site. Contact your network administrator for assistance.; Rolling Over."

The call has ended.; Local user initiated hangup.

Failed Attempt; "The far site is busy. Try the call again later.; Rolling Over."

Failed Attempt

Failed Attempt; "The call has ended."

I can't understand the following reasons:

1:Failed Attempt; "The call has ended."------it means The MCU hangup?

2:Failed Attempt

3:Failed Attempt; "Your call could not be completed because the call was routed through an intermediate network that does not service the far site. Contact your network administrator for assistance.; Rolling Over."-----it means EndPoint can't reach the other site?

4:Failed Attempt; "The far end system is capable of accepting the call, but the call was rejected for an unknown reason. Contact your network administrator for assistance.; Rolling Over."----network  problem?

[PolyTay]

Hello Drifter,

I understand that you are seeing a few connection issues with your HDX. The error messages that you mentioned are a sign of a possible firewall configuration problem on your network. Are the below ports open on your firewall currently?  

3230-3243 TCP

3230-3341 UDP

1720 TCP

The specific errors are usually related to network configuration and you may want to speak with your IT support personal on these issues.