To troubleshoot the issue, I reinstalled Flarum on a different server and installed only the "HamCQ Filter Plus" plugin from the administrator, without installing any other third-party plugins. I also enabled and configured the Alibaba review. After that, I posted this message, but the same problem occurred again. The content of my post is fine, and the results from the Alibaba Content Security Console show that it has been approved, but the Flarum forum still shows the post as pending review…
Currently, Flarum has no third-party plugins installed, and we are troubleshooting plugin conflicts. The settings for HamCQ Filter Plus only include the parameters for Alibaba Cloud, which should not be a problem.
I'm not sure if this is a problem with the Flarum version. I have installed the latest version, and here are the other settings:
Flarum1.8.5
PHP8.1.27
MySQL5.7.30-log
The HamCQ Filter Plus settings screenshot is shown below.

