To authorize HDE One to send emails on your behalf you will have to include it in your SPF record. The SPF record mechanism used by HDE One is shown below.
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​include:your-domain.hdemail.jp

You will have to replace the "your-domain" above with the actual value in your Connection Settings File.

For more information on enabling DKIM please contact HDE One support.
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Create a free OnDMARC account to test your configuration.