You configured storage1 to allow access from the subnet in VNet1 by using a service endpoint. You must ensure you can use that service endpoint to reach the read-only endpoint of storage1 in the paired Azure region. What should you do first?

To access the read-only endpoint of storage1 in the paired Azure region via a service endpoint, you must first have a virtual network in that paired region. Service endpoints are configured per subnet within a virtual network. Without a VNet in the paired region, there's no network infrastructure to host the subnet from which you would access the storage account's read-only endpoint. Failing over storage1 is not necessary as you're accessing a read-only endpoint, not performing a full disaster recovery. Configuring firewall settings is a subsequent step after establishing network connectivity. Creating another service endpoint is also a later step, dependent on having a VNet and subnet in the target region.