When trying to upload files to the Wordpress media library I encounter the following error:
Unexpected response from the server. The file may have been uploaded successfully. Check in the Media Library or reload the page.
I enabled debugging mode in WP by adding
define('WP_DEBUG', true);
define('WP_DEBUG_DISPLAY', true);
define('WP_DEBUG_LOG', true);
to my wordpress config file.
After taking a look at debug.log there seems to be a problem with one of the WP core files PHP Fatal error: Uncaught Error: Cannot unset string offsets
The function throwing the error is clean_dirsize_cache
Line 8381: unset( $directory_cache[ $path ] );
I've already tried the following:
- Allocated more memory in php.ini
- Changed limit for max file sizes
The error happens on every file I try to upload, file size or file type doesn't seem to matter.
As I'm not experienced with Wordpress and I haven't worked on this site previously at all I'm not quite sure what caused this to start occuring.