Still Not Uploading files

Hi, I have a lot of issues with this plugin, I still can not upload any files, it seems to only want to upload any picture under 300×300 and will not upload any videos either. I have tried a lot of troubleshooting. I been to my Cpanel and allowed lots more upload and time, I’ve tried different themes and different websites. I always get “Oops! That page can’t be found”i have changed post names reset premlinks, changed settings in attach doc settings. I need help, please.

The page I need help with: [log in to see the link]