Is there a size limit on files uploaded to Dropbox, Amazon S3, etc.?

Yes, the file size limits are as follows:

          • Dropbox – 20 GB;
          • Google Drive – 5 TB;
          • Amazon S3 – 5 TB;
          • Microsoft OneDrive – 10 GB;
          • OpenStack Swift – 5 GB;
          • WebDAV servers – depends on the server settings (usually 50 MB);
          • FTP and SFTP servers – depends on the server settings.
          • Box – depends on the type of account:
            • 250 MB – Free Personal account;
            • 2GB – Starter;
            • 5GB – Business/Enterprise account.