Unable to upload large files or no data received on "Save Article" page
If you are unable to see any content after clicking the "Preview Article" button or unable to attach large files, then it is due to size of post data. If the size of post data is greater than post_max_size , the $_POST and $_FILES super-globals are empty, resulting in no content being sent to "Save Article" page. In easy terms, the uploaded files are too large for your server to handle. Therefore, PHP discards POST data because of request exceeding post_max_size variable.
In order to fix this issue, you need to increase the value of post_max_size variable in php.ini file or upload the files with total file size lower than post_max_size value. Also, the post_max_size value must be larger than the upload_max_filesize value.
Also take the notes below from the Official PHP Documentation into account:
Sets max size of post data allowed. This setting also affects file upload. To upload large files, this value must be larger than upload_max_filesize. If memory limit is enabled by your configure script, memory_limit also affects file uploading. Generally speaking, memory_limit should be larger than post_max_size which in turn should be larger than upload_max_filesize . So, you might also need to change the value of memory_limit variable in php.ini file
memory_limit > post_max_size > upload_max_filesize
IMPORTANT : Please make sure to save the changes in php.ini file and then restart your web server for the changes made in php.ini to take effect.