When provisioning error found, "Operation FAILED: Invalid MAC"

Issue

• When trying to provision, from vmware, the following error occurs in /var/log/foreman/production.log

2015-12-16 14:56:35 [I] Processing by HostsController#create as */*
2015-12-16 14:56:35 [I]   Parameters: {"utf8"=>"✓", "authenticity_token"=>"8bCaqnHeXkYjZS0tP42M+KtNsVOghiELEHnbpQYBs+0=", "host"=>{"name"=>"invalidmac", "organization_id"=>"4", "location_id"=>"3", "hostgroup_id"=>"3", "compute_resource_id"=>"1", "lifecycle_environment_id"=>"2", "content_view_id"=>"9", "environment_id"=>"9", "content_source_id"=>"1", "puppet_ca_proxy_id"=>"1", "puppet_proxy_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "compute_attributes"=>{"cluster"=>"5c82a57e-ab50-4dc2-95cb-97003330d73c", "template"=>"", "cores"=>"1", "memory"=>"268435456", "interfaces_attributes"=>{"new_interfaces"=>{"name"=>"", "network"=>"49590203-8812-491b-a1fa-3834808431bf", "_delete"=>""}}, "volumes_attributes"=>{"new_volumes"=>{"size_gb"=>"", "storage_domain"=>"c35e9555-795a-4e68-840a-8f4f0e934312", "_delete"=>"", "id"=>"", "preallocate"=>"0"}}, "start"=>"1"}, "domain_id"=>"1", "realm_id"=>"", "mac"=>"", "subnet_id"=>"2", "ip"=>"xx.xx.xx.xx", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "identifier"=>"", "name"=>"", "domain_id"=>"", "subnet_id"=>"", "ip"=>"", "managed"=>"1", "virtual"=>"0", "tag"=>"", "attached_to"=>""}}, "architecture_id"=>"1", "operatingsystem_id"=>"1", "provision_method"=>"build", "build"=>"1", "medium_id"=>"7", "ptable_id"=>"7", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"3-Users", "enabled"=>"1", "comment"=>"", "overwrite"=>"true"}, "capabilities"=>"build image", "provider"=>"Ovirt"}
2015-12-16 14:56:36 [W] Operation FAILED: Invalid MAC 
2015-12-16 14:56:36 [I]   Rendered common/500.html.erb (7.3ms)
2015-12-16 14:56:36 [I] Completed 500 Internal Server Error in 1086ms (Views: 8.8ms | ActiveRecord: 10.1ms)