Files "blank" when attempted to upload

Hello all,

I am having an issue that when I have a file which I attempt to upload to proton drive or as an email attachment to the outlook website through my browser I get an error saying it is a “blank file”. When I upload anyway and then open it - the uploaded file is in fact blank and has a size of 0B. This has occurred with word and PowerPoint files saved using both onlyoffice and libreoffice. Tested on many different browsers: mullvad, Firefox, librewolf, ungoogled chromium, trivalent. This also occurs when trying to attach these files to an email (Thunderbird). The same error occurs with PDFs but if I convert to a trusted PDF in a disposable before trying it is now fixed. The files are not blank when opened in a file manager prior to attempting the above. Context: Qubes OS 4.3.1. Lenovo nano X1 gen 1. Fedora-44-gnome template. Everything is up to date and seems to work otherwise. I have not done much tinkering. Has anyone encountered this or know what might be causing this?

Thank you for reading.

I’ve never encountered such an error before. Does it also happen on other network connections (such as with mobile hotspot?)

Yes that is correct. My home and work WiFi and my mobile hotspot too. I’m using proton VPN. Downloading files works well. Given it occurs when trying at attach to an email in Thunderbird (before I try sending it) I had assumed it is not a network issue.