Yes the solution that i have provided is for uploading using the media library.
Is it working fine when uploading images using the media library?
Can you please try enabling WP_DEBUG mode and debug logging? To do this, just go to wp-config.php include this:
You might already have a line for WP_DEBUG, so just make sure it's set to true. This will create a log file under wp-content/debug.log with detailed information.
If you'd like to avoid end users seeing error messages, you can include this as well:
This will prevent errors from being displayed, but you can still find them in the log file. For information on this, checkout this wpmu.org article.
Let me know what errors if any you are getting!