ECS tasks in a Cluster, not linking between them.

Hello, im stuck in this topic. And i dont find clear information for me to solve it. I have different tasks in a Cluster, each task have one container. One container is a DB and needs to be linked with the other containers. The Tasks are in Bridge mode and in the same VPC. But seems like they are not getting link or connected. I still recieve error from one container to reach the DB. Can any one tell me if I should do something else to connect them? Thanks