Hosts of cluster are down

I have a cluster with 3 hosts, they are all down.
How I can start them?

Welcome to the MongoDB Community Forums @Fabiano_Andrade.

I assume you are using MongoDB Atlas because of the category you chose for this discussion.

For operational issues with Atlas please contact the support team.

If this is actually an on-premises deployment, please provide more information on your environment (MongoDB version, O/S version, and any relevant errors/shutdown messages from the MongoDB logs).