I hate asking a vague question like this but I'm really at loss as to my current problem. I'm setting up a new site and image uploads fail on my production site (both in custom and content type forms). The failure occurs when a file is sufficiently large (greater than ~4mb). I believe the failure has more to do with something timing out rather than a limit to file size. At my office where the connection is good I can upload an 8mb image but on my slower home connection I can't upload more than a 4mb image. The upload seems to consistently timeout at about 20 seconds.
When the upload fails the form itself doesn't provide any feedback. The little blue spinner just disappears and the remove button never appears. The only feedback I receive is through the browser's console. I'm getting a
HTTP Result Code: 400 error. Paths are good because like I said I'm able to successfully upload when the image or file is sufficiently small.
My relevant php settings are:
max_execution_time 300 max_input_time -1 post_max_size 18M upload_max_filesize 16M
I'm able to confirm these php settings through a phpinfo.php page so I'm reasonably confident it's not this.
I'm running Drupal 8.7.6 on CentOS7 with PHP 7.2.21.
Does anyone have a good guess as to what my problem could be? I'm sorry this is vague and most likely not an issue with Drupal. Thanks, I appreciate any hints you might provide.