Upload Error - can't upload large files to threads

[gfxhelp.com]

I can upload files, but when I tried to upload a 50MB file I got an error after a few minutes saying "Your submission could not be processed because a security token was missing." Originally, I had the upload limit too low in my php.ini, I can now upload files that are around 10MB with no problem, but not very large files. Any ideas? I'm talking about uploading files when creating threads for clarification.

Thanks

[Dismounted]

<a href="https://vborg.vbsupport.ru/search.php?do=process&query=security%20token&forumchoice%5B%5D=-1&titleonly=1" target="_blank">Missing Security Token</a>