@Thomaz Moreira​ :

It sounds like there might be an issue with the network configuration of your Databricks cluster. Here are a few things you can check:

1. Make sure that your Databricks cluster is in the same VPC as your service in the other AWS account, and that it is properly configured to use the transit gateway as its default route to reach resources in other accounts.
2. Check the network security group (NSG) rules for your Databricks cluster. Make sure that the NSG allows traffic to and from the IP addresses or security groups of the resources in the other AWS account that you are trying to access.
3. Check the route tables for your subnets. Make sure that there is a route that allows traffic to flow from your Databricks cluster to the transit gateway, and that there is a route that allows traffic to flow from the transit gateway to the service in the other AWS account.
4. Check if there is any network ACL (NACL) rules that might be blocking traffic from your Databricks cluster to the transit gateway or from the transit gateway to the service in the other AWS account.
5. If you are using a VPN or Direct Connect to connect to the transit gateway, make sure that the routing configuration on the on-premises network is correct and allows traffic to flow to and from the resources in the other AWS account.

I would recommend checking these configurations and verifying that they are properly set up. If you still cannot connect to your service, it may be helpful to enable VPC flow logs to troubleshoot the traffic flow between your Databricks cluster and the service in the other AWS account.