Beyond just pinging the domains used by Cyber Crucible to make sure that your endpoint can reach all of the correct network address, below are some example curl commands that can be used to confirm a valid TLS/SSL connection can be made in both directions.
https://ransomwarerewind-agents.auth.us-west-2.amazoncognito.com
curl -X POST -H "Content-Type: application/x-www-form-urlencoded" "https://ransomwarerewind-agents.auth.us-west-2.amazoncognito.com/oauth2/token?grant_type=client_credentials&client_id=74pcqm7ftftq0l892vj3lgcbkg&scope=http://localhost:5000/agent.full" -H "Authorization: Basic NzRwY3FtN2Z0ZnRxMGw4OTJ2ajNsZ2Nia2c6MTBqYXA5ZjFlZG45aDU2MTUybGZmaGR1MGFibTJyZmFmbDk1MzQ3Z3B1aGx2cjZyOG9lbA=="