Cannot connect to AWS Redis cluster over SSM session

I have set up a Redis cluster in an AWS VPC and am able to connect through a SSM session

aws ssm start-session --target $bastion_instance_id --profile $profile \
    --document-name AWS-StartPortForwardingSessionToRemoteHost \
    --parameters host="$cluster_configuration_endpoint",portNumber="6379",localPortNumber="6380"


redis-cli -h -p 6380 ping

When entering the same info over RedisInsight, I get a “Could not connect to, please check the connection details.” error

What could be the issue? All network authorizations should be OK as the Redis CLI is able to connect to the cluster