I had Malwarebytes premium antivirus on pc and Malwarebytes browser guard, they both didn't let me access anonfiles, got flagged as Trojan site. It didn't really matter to me because there are previews for BTQ5 from 1to60.
Had to stop using MBam because RAM throttle, CPU excess usage and other issues. I tried to fix the problem with customer support but the problem kept coming back. Few weeks ago i gave up and started using Eset, had no issue watching the previews.
I was surprised that anonfile did not even get flagged as malware, PUPs and PUMs.
TL;DR. IMHO its false positive.