“Unexpected response from server” error when trying to upload any .mp4 file over 100MB

If you are using cPanel this may be triggered by a ModSecurity rule that block uploaded files higher than the predefined limit they use.

This is a very tricky error to spot since it’s only logged serverwise. Within this log: /usr/local/apache/logs/error_log

Here is a cPanel tutorial which explains why it happens and how to override the limit: https://support.cpanel.net/hc/en-us/articles/11596999975447–ModSecurity-Request-body-Content-Length-is-larger-than-the-configured-limit