can you add some details
communication manager version
AE Services version
77 is a fairly obscure TSAPI error code
The TSAPI Service detects that it cannot
provide the service due to the failure or
shutting down of the communication link
between the Telephony Server and
Communication Manager. The TSAPI Service
sends this error for every outstanding CSTA
request for every ACS Handle affected.
Although the link is down or Communication
Manager is out of service, the TSAPI Service
remains loaded and advertised. When the
TSAPI Service is in this state, all CSTA
Service requests from a client will receive a
negative acknowledgment with this unique
Is this 100% reproducible?
The logs you provided do not shed any light on what occurred across the switch connection to communication manager from AE Services. To have us take a look at this please open a DevConnect Technical Support request, and include the TSAPI, csta and server log.YYYYMMDD trace files (https://www.devconnectprogram.com/site/global/products_resources/avaya_aura_application_enablement_services/support/faq/tsapi/index.gsp#10
) the log.YYYYMMDD file should be in '/opt/mvap/logs for when you are performing these actions.