File upload validation fails for uploaded rule

PHP Code:

$files = $this->request->getFiles() ; 


Dump this $files and read manual, get real error exception message https://codeigniter4.github.io/CodeIgnit....html#id14
and bug test button !empty('string') - its error notice

Hi,
Thanks for your suggestion.
I tried to get file errors but according to file message and error code 0 (zero), there is no error with the file yet it fails to pass the validation still.
I'm kinda stumped as to why it is failing.
Any other suggestions are much appreciated.
Thank you.

PHP Code:

$file = $this->request->getFile('sky_csv_file');
 echo $file->getErrorString(); /*returns: The file uploaded with success.*/
echo $file->getError(); /*returns: 0*/