For migrations to Azure, one NIC must be configured as the primary NIC for the target VM. If the workload has only a single NIC, it is automatically set as the primary NIC. If a workload has multiple NICs, the first NIC is configured by default as the primary NIC.
To configure a NIC as the primary NIC:
In the Workload dialog, scroll to the Network Interfaces panel, then click Edit.
Select the NIC, then select the Set as primary check box.
Click Save to update the network interface settings.