How to connect to public Amazon MSK cluster using SASL SCRAM using Confluent C# Kafka

I am attempting to connect to a public Amazon MSK cluster from a project using Confluent C#. I have a user specified in the secret manager in my Amazon MSK resource, and I have a topic created that can consume messages from within my VPC using SASL SCRAM authentication.

However, when I try to access the same topic using SASL SCRAM authentication with the same user using the public resource from my Confluent C# project, the data does not get consumed and I do not see any metrics or errors in the Amazon MSK resource. Using Confluent C#, here is an example of the parameters I am setting:

BootstrapServers = PublicKafkaBootstrapServers,
SaslMechanism = SaslMechanism.ScramSha512,
SecurityProtocol = SecurityProtocol.SaslSsl,
SaslUsername = Username, // same as secrets manager
SaslPassword = Password, // same as from secrets manager
Acks = Acks.All // msk cluster configuration has default.replication.factor=1, min.insync.replicas=1

What steps do I need to take in my Confluent C# project, or in my Amazon MSK cluster, to enable public access to topics in my Amazon MSK cluster?

Thanks in advance, let me know if more information is required.