OPS3.3.0.8 Email of "Preprint Posted Acknowledgement" is not send

Dear all,

I am using with OPS
The “Email Templates” column in “Workflow Settings” says as follows, but the email is not actually sent.
No error is printed on the screen or in the server logs.

“This email, when enabled, is automatically sent to an author when the preprint is posted online on the server.”

I can’t figure out the cause. Is this feature currently disabled?

By the way, the “Submission Acknowledgement” email has been sent without any problems.