Post machine migration
If you just migrated your disk to another machine with a different ip, you should do the following set of commands:
crossbox config set -k public_ip_address -s "new_ip_address" crossbox sync all
After that you should wait at least 10 minutes until CrossBox recognizes the new environment.
Then you should verify if all services are running:
Make sure all firewall rules are working correctly and check if the instance is accessible once again.