aaPanel_Kern
then on one server it was a permissions problem even though the folders were set to 777 or 755 I still have to figure out why this problem occurred but formatting it now is I will never know.
On another server, on the other hand, some extensions such as xls are not being uploaded, giving the error File Upload Failed, another error, even if the upload is set to 100mb, 7mb is always displayed.