Lambda function throwing : TooManyRequestsException, Rate exceeded

When the Lambda function is invoked, occasionally I see the following error for the function even though there is no Load running or not many lambda functions running. While the throttling and quota requests are set to default running in the Mumbai region, but this error is observed even when no load is running.. How do I determine with configuration needs to be increased to address this problem ?

2022-05-17T10:01:13.555Z 84379818-c8b8-44a3-b353-2c9f7f8f5e48 ERROR Invoke Error { "errorType": "TooManyRequestsException", "errorMessage": "Rate exceeded", "code": "TooManyRequestsException", "message": "Rate exceeded", "time": "2022-05-17T10:01:13.553Z", "requestId": "c3dc9f1b-d7c3-40d5-bec7-78e19dc2e033", "statusCode": 400, "retryable": true, "stack": [ "TooManyRequestsException: Rate exceeded", " at Request.extractError (/var/runtime/node_modules/aws-sdk/lib/protocol/json.js:52:27)", " at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:106:20)", " at Request.emit (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:78:10)", " at Request.emit (/var/runtime/node_modules/aws-sdk/lib/request.js:686:14)", " at Request.transition (/var/runtime/node_modules/aws-sdk/lib/request.js:22:10)", " at AcceptorStateMachine.runTo (/var/runtime/node_modules/aws-sdk/lib/state_machine.js:14:12)", " at /var/runtime/node_modules/aws-sdk/lib/state_machine.js:26:10", " at Request.<anonymous> (/var/runtime/node_modules/aws-sdk/lib/request.js:38:9)", " at Request.<anonymous> (/var/runtime/node_modules/aws-sdk/lib/request.js:688:12)", " at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:116:18)" ] }