After placing required JARs inside <PRODUCT_HOME>/lib as stated in WSO2 official doc link , The above mentioned issue got resolved.

List of JARs added:

• apache-client-2.20.26.jar

• auth-2.26.20.jar

• aws-core-2.26.20.jar

• checksums-2.26.20.jar

• checksums-spi-2.26.20.jar

• endpoints-spi-2.26.20.jar

• http-auth-aws-2.26.20.jar

• http-auth-spi-2.26.20.jar

• http-client-spi-2.26.20.jar

• identity-spi-2.26.20.jar

• json-utils-2.20.26.jar

• metrics-spi-2.20.26.jar

• profiles-2.26.20.jar

• protocol-core-2.20.26.jar

• reactive-streams-1.0.4.jar

• regions-2.26.20.jar

• retries-spi-2.26.20.jar

• sqs-2.26.20.jar

• third-party-jackson-core-2.20.26.jar

• utils-2.26.20.jar

• aws-json-protocol-2.26.20.jar

• http-auth-2.26.20.jar

• sdk-core-2.26.20.jar

• retries_2.26.20.jar

  Note: As of now, amazon SQS Connector 2.X related document only updated in WSO2 site, not V3.X.

  PS: In local setup, Though i didn't place any JAR manually to server's lib folder , it works fine