目标文件夹路径确实存在问题.

There is definitly a problem with the destination folder path.

您的上述错误消息说，它希望将内容放入目录/files/grantapps/中的文件中，该文件可能不在您的vhost目录中，但在系统中的某个位置(请参见前导绝对斜杠)

Your above error message says, it wants to put the contents to a file in the directory /files/grantapps/, which would be beyond your vhost, but somewhere in the system (see the leading absolute slash )

您应该仔细检查:

• 目录/home/username/public_html/files/grantapps/确实存在吗?
• 包含循环，而file_put_contents-Statement包含绝对路径/home/username/public_html/files/grantapps/

• Is the directory /home/username/public_html/files/grantapps/ really present.
• Contains your loop and your file_put_contents-Statement the absolute path /home/username/public_html/files/grantapps/