Cannot connect Amazon Keyspaces using rails CQL

Question

I'm using the below configuration in the rails config/cequel.yml.

development:
  host: 'cassandra.ap-south-1.amazonaws.com'
  username: 'username'
  password: 'password'
  port: 9142
  keyspace: 'keyspace'
  max_retries: 3
  retry_delay: 0.5
  newrelic: false
  ssl: true
  server_cert: '/sf-class2-root.crt'

But when I run rake cequel:keyspace:create, it gives the following error:

Cassandra::Errors::NoHostsAvailable: All attempted hosts failed: 3.6.70.138 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.133 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.132 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.136 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.145 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.140 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.134 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.143 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.139 (Cassandra::Errors::ServerError: Internal Server Error), 3.6.70.135 (Cassandra::Errors::ServerError: Internal Server Error)

Same host is working on cli cqlsh