URL: Blacklist of internal school documents?

Avast: 19.8.2393 (build 19.8.4793.544)
Firefox: 70.0.1 (64-bit)
Windows 10

We have recently been experiencing a URL: BLacklist of documents that were uploaded to our school’s web portal. This hasn’t ever occurred before. I checked the validity of the PlusPortals.com website via VirusTotal https://www.virustotal.com/gui/url/7336d96dab3c4e340858137cea7476a648d274c329aeceea1021c65fb90ee544/detection and everything seems to come back fine.

This is the error I received when I tried to replicate an error request from another staff member.

https://i.imgur.com/GCvkRC0.jpg

This is the screenshot sent to me from another staff member.

https://i.imgur.com/ZptplJm.png

Any assistance would be greatly appreciated.

Report a false positive (select file or website)
https://www.avast.com/false-positive-file-form.php

https://forum.avast.com/index.php?topic=14433.msg1289438#msg1289438