packer-vsphere-template-error2

    ubuntu-16.04-x86_64 (vsphere): Uploading output-ubuntu-16.04-x86_64/packer-ubuntu-16.04-x86_64.vmx to vSphere
2017/09/21 13:48:49 [INFO] (telemetry) ending vsphere
2017/09/21 13:48:49 ui: ==> ubuntu-16.04-x86_64: Running post-processor: vsphere-template
2017/09/21 13:48:49 [INFO] (telemetry) Starting post-processor vsphere-template
==> ubuntu-16.04-x86_64: Running post-processor: vsphere-template
2017/09/21 13:48:49 [INFO] (telemetry) ending vsphere-template
2017/09/21 13:48:49 [INFO] (telemetry) found error: Unknown artifact type, can't build box:
2017/09/21 13:48:49 Deleting original artifact for build 'ubuntu-16.04-x86_64'
2017/09/21 13:48:52 ui error: Build 'ubuntu-16.04-x86_64' errored: 1 error(s) occurred:

* Post-processor failed: Unknown artifact type, can't build box:
2017/09/21 13:48:52 Builds completed. Waiting on interrupt barrier...
2017/09/21 13:48:52 machine readable: error-count []string{"1"}
2017/09/21 13:48:52 ui error:
==> Some builds didn't complete successfully and had errors:
2017/09/21 13:48:52 machine readable: ubuntu-16.04-x86_64,error []string{"1 error(s) occurred:\n\n* Post-processor failed: Unknown artifact type, can't build box: "}
2017/09/21 13:48:52 ui error: --> ubuntu-16.04-x86_64: 1 error(s) occurred:

* Post-processor failed: Unknown artifact type, can't build box:
2017/09/21 13:48:52 ui:
==> Builds finished but no artifacts were created.
Build 'ubuntu-16.04-x86_64' errored: 1 error(s) occurred:

* Post-processor failed: Unknown artifact type, can't build box:

==> Some builds didn't complete successfully and had errors:
--> ubuntu-16.04-x86_64: 1 error(s) occurred:

* Post-processor failed: Unknown artifact type, can't build box:

==> Builds finished but no artifacts were created.
2017/09/21 13:48:52 waiting for all plugin processes to complete...

The most tricky thing here is that the artifactId is nil...