Cannot add SEPM to EDR: error message: "Failed to configure SEPM controller connection"
In the atpapp.error.log you see
2021-09-20 06:28:30,293 ERROR http-nio-127.0.0.1-8010-exec-2 (CentralManagerServiceImpl.java:validateSepm:5071) Error when trying to connect to SEPM. Exception : name=ERROR_SERVICE_UNAVAILABLE, description=Can't get response from SEPM Server
com.symantec.atp.central_manager.rmi.exception.SepmCommunicationException: name=ERROR_SERVICE_UNAVAILABLE, description=Can't get response from SEPM Server
and communication_manager.log you see
2021-09-20 06:28:30,286 INFO RMI TCP Connection(16714)-127.0.0.1 (SepmRestApi.java:simpleRequest:441) Updating Sepm connection health for request [https://SEPMURL:8446/sepm/api/v1/identity/authenticate]
2021-09-20 06:28:30,287 INFO RMI TCP Connection(16714)-127.0.0.1 (SepmRestApi.java:updateConnectionStatus:500) Update Status for Server : SEPMURL Domain : SEPMDOMAIN with status code: 503
2021-09-20 06:28:30,287 ERROR RMI TCP Connection(16714)-127.0.0.1 (SepmCommunicationMgrImpl.java:validateSepm:2514) Failed to connect to SEPM. Most probably because of bad/invalid certificate
2021-09-20 06:28:30,291 ERROR RMI TCP Connection(16714)-127.0.0.1 (SepmCommunicatorRemoteImpl.java:validateSepm:895) Error when trying to connect to SEPM. Exception : name=ERROR_SERVICE_UNAVAILABLE, description=Can't get response from SEPM Server
2021-09-20 06:28:36,818 INFO RMI TCP Connection(16714)-127.0.0.1 (SepmRestApi.java:updateRequestUrl:331) failed to get resolved address for SEPM controller [0], requestUrl: [https://SEPMURL:8446/sepm/api/v1/version]
2021-09-20 06:28:36,847 INFO RMI TCP Connection(16714)-127.0.0.1 (SepmRestApi.java:updateConnectionStatus:500) Update Status for Server : SEPMURL Domain : SEPMDOMAIN with status code: 200
2021-09-20 06:28:36,850 INFO RMI TCP Connection(16714)-127.0.0.1 (SepmRestApi.java:updateRequestUrl:331) failed to get resolved address for SEPM controller [0], requestUrl: [SEPMURL:8446/sepm/api/v1/identity/authenticate]
http 503 Service unavailable refers to the SEPM response, line 3: "Most probably because of bad/invalid certificate" is spurious in this case.
The SEPM can fail to respond to the EDR when it is too busy or the service has failed.
SEDR Version: 4.6.5-32
SEPM version: 14.3.4615.2000
The SEPM was unable to accept incoming web requests on the API port, preventing the communication with EDR.
To confirm whether SEPM is up