After that.
No changes have been made, but it is now displayed when left unattended for a day.
It is very mysterious, but it was solved. (But I’m still worried because the cause is unknown.)
Is it a server response problem or a cache problem??
For users with similar problems, I will leave this trick as a reference.
Similarly, if the PDF is not displayed, it may be solved if you leave it for a few days. How about trying it?
Thank you for your patience.
PS: Google Translate is very useful. Thank you!