What are the call history end reason codes and their meaning?

What are the call history end reason codes and their meaning?

A list of call history codes and their meaning.
Call History End Reasons
End Reason Code
End Reason Definition
UNKNOWN
The call ended for an unknown reason.
NO_RESOURCES
Needed server resources are not available.
USER_INITIATED
User-initiated cancel/bye.
UNAVAILABLE
The called party is not registered (timeout).
SIGNED_OUT
The called party is not registered (signed out).
NOT_RESPONDING
The called party did not respond to the invite.
BUSY
The called party is busy on another call.
LIST_NOT_SYNCED
Call to a list that is not in sync.
GROUP_FULL
No more parties may join the group.
NO_PRIVS
No privileges for call type (for example, broadcast).
DND
The user's phone is on DND.
CIRCUIT_CALL
Switched to circuit call. The user is on a voice call.
CALL_DROPPED
The other party lost connection.
CRYPTO_ERROR
Security Error.
SILENT
The user's phone is in silent mode.
USER_REJECT
The user rejected the alert call.
NO_ANSWER
There was no answer to the alert call.
OVERRIDE
Someone of higher priority initiated a call to the user.
DUPLICATE_GROUP
Received an invite to a group, but call for that group is already in session.
REMOVED_FROM_GROUP
Member has been removed from the group while in a group call.