"org.camunda.bpm.engine.rest.spi.ProcessEngineProvider: Error reading configuration file" when camunda Rest API is invoked

We use camunda rest api to get the user task information and complete the task. Recently we are having intermittent issues when working with these api’s. Please check below for sample request/response

Camunda rest endpoint :https://pcu-test.it.com/deployBpm-0.0.1-SNAPSHOT/engine/engine/history/variable-instance?taskIdIn=1007573&variableName=USER_INPUTS

Response : {

"type": "ServiceConfigurationError",
"message": "org.camunda.bpm.engine.rest.spi.ProcessEngineProvider: Error reading configuration file"

}

Please let me know if anyone has information about this error.

Thanks in Adavance!

why are you not using the <servername>:<port>/engine-restend point, that is the one intended for external communication.