I think I determined what this error means. From https://devconnect.avaya.com/secure/download/AES/4.1/02_300544_i3.pdf?
REQUEST_TIMEOUT_REJECTION (78) The TSAPI Service did not receive the response of a
service request sent to Communication Manager
more than 20 seconds ago. The timer of the request
has expired. The request is canceled and negatively
acknowledged with this unique error code. When this
occurs, the communication link between the TSAPI
Service and Communication Manager may be
congested. This can happen when the TSAPI Service
exceeds its capacity.
Where does the TSAPI Service and Communication Manager run? Is there a way to monitor the load?
Thanks in advance.