Splunk Add-on for Kafka: "CredException: Get session key failed" setting up a heavy forwarder to forward data to Splunk Cloud

Hello, I'm setting up a Heavy Forwarder to forward data from a Kafka topic to Splunk Cloud using Splunk add-on for Kafka. However, I'm currently encountering credential issue: ERROR pid=23104 tid=MainThread file=kafka_config.py:_do_send:545 | Failed to dispatch task to forwarder https://input-prd-xxxxxx.cloud.splunk.com:9997 ... Splunk_TA_kafka/bin/splunktalib/credentials.py", line 77, in get_session_key raise CredException("Get session key failed.") CredException: Get session key failed. The credential that provided was the one used to log into the Heavy Forwarder (the local Splunk Instance). Perhaps, I have set things up incorrectly somewhere. I find the official documentation of the Addon is quite confusing with a not so clear instructions. Any step by step instruction would be greatly appreciated. Thank you.