升级X3后 帖子编辑好后点击发表帖子就提示该页面The requested URL /thread-2656-1...

提示错误页面

升级X3后 帖子编辑好后点击发表帖子就提示该页面
Not Found

The requested URL /thread-2656-1-1.html was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

补充，远程图片下载到本地后发帖出现白屏，但帖子是会成功发出，没有图片

发表的帖子中有图片吗？如果有图片可以把相应版块的“禁用图片附件添加水印”选择为否，再发表帖子。