All FTP uploads are limited to files under 500MB.
If you need to have a file larger than 500MB in your web space, you will need to divide it into pieces and reassemble them after downloading them separately.
To do this, you need to create a spanned ZIP file, which is supported by all popular archiving software. This is usually under a ‘Split to volumes’ option, and you can adjust the size of each volume to distribute the size as needed.
Once the file has been distributed to the volumes, upload all the volumes and the ZIP file to your account, and then ask the recipient to download all the files.
If you are using your webspace for file transferring, please consider finding a cloud-based data transfer system, or consider upgrading to a VPS, Hybrid or Dedicated Server.
Please note that hosting packages do have a monthly soft cap of 25GB for file distribution (the uploading and downloading of files). Please do not intentionally bypass this limit by running a large file distribution service.