Reply notification not send to visitors when I reply in backend

Hi,
I love this wonderful plugin,it’s beautiful and fast to load.

But I’m facing a trouble that when someone leave comment on a post , I usually reply to him in WordPress admin default area “Comments” as this screenshot:
https://upload.cc/i1/2020/10/12/ARwKyD.png

Then after I replying,the visitor will receive a notification email which mentions I’ve replied.
Everything works well until installing wpDiscuz.
After installing wpDiscuz,visitors will not receive a notification email when I reply to him.

But!!!If I reply his comment in frontend like this screenshoot ,he will receive the notification email.
https://upload.cc/i1/2020/10/12/Pf3BrE.png

I have tested dozens of times with different types of email as visitor,includes hotmail/gmail/yahoo mail/outlook…etc .
The result is I can only reply to visitor at frontend, so that the visitor can receive the notification Email that his comments was replied.
Once I reply in the backend(WordPress admin area “Comments”),visitors will not receive the notification Email.

And I also test as someone subscribes to comments , he also can receive Email notification if others reply that comments.
includes me(The premise is that I have to reply to the comment on frontend. If I reply the comment in backend, the subscribers won’t receive it.)

All the problems come from replying the comments in backend (the WordPress default “Comments page”).
If I reply the comments in frontend, all email notifications can be sent normally.
This also means that all visitors reply to others in frontend, and email notifications can be sent normally.
And I am used to replying comments on the WordPress default “Comments page”, email notifications cannot be sent unless I reply to visitors’ comment in frontend.
Because I hope I can still reply the comment on the WordPress default “Comments page”, it would be great if this problem can be solved

I am sure that my website and the host can send mail to my Email normally, including the notification Email of visitor’s comments and subscription .

I don’t know what else is wrong.

Here are screenshots of my settings in wpDiscuz:
1.Setting>Subscription and User Following
https://upload.cc/i1/2020/10/12/Q4Xzau.png

2.Default Form(I only have a “default form to posts”)
https://upload.cc/i1/2020/10/12/epqaCL.png

3.WordPress Discussion Settings
https://upload.cc/i1/2020/10/12/Mm5yp1.png