When you're using an Nginx server and you're unable to upload big-size audio or video, it is most probable the size of the uploaded file is larger than the in-memory buffer reserved for uploads. So, to fix this issue, you'll need to increase the MaxRequestLen directive on the server.
NOTE:
If this
If this
MaxRequestLen directive is only available in the Apache server then you have to increase the client_body_buffer_size and client_max_body_size directives on the Nginx server.If you've activated the FastCGI on your site and still hitting the same issue, you'll need to increase the following directive's value on /apache/mods-enabled/fcgid.conf (It might differ between servers. Please consult your hosting provider regarding this.)
FcgidMaxRequestLen=5073741824FcgidMaxRequestInMem=5073741824FcgidConnectionTimeout=3000
If you are unsure how to do this, it's best to contact your hosting provider for clarification.