In VMware NSX for vSphere 6.4.1, during first DLR deployment, only portgroups from VXLAN backed VDS are displayed on HA network selection and unable to select portgroups from VDS that does not have VXLAN configured.
In 6.4.1, portgroups are not displayed for HA interface unless they are on VXLAN backing VDS at DLR deployment time.
This issue is resolved in VMware NSX Data Center for vSphere 6.4.2 or later.
Workaround:
Temporarily use portgroup from VXLAN backing VDS to deploy DLR and configure correct portgroup after deployment.