https://helpcenter.veeam.com/docs/vbr/cloud/cloud_failover_plan_gateways.html
Step 4. Specify Default Gateways - Veeam Backup & Replication Veeam Cloud Connect Guide
At the Default Gateways step of the wizard, check and, if necessary, specify default gateways in every IP network in the production site that are used by VMs...
default gatewaysconnect guidestepspecifyveeam