RESOLVED: it was caused by the app being flatpak. use Flatseal!
I have a network drive mounted to my computer (PopOS). I have read & write access to everything in the drive and can drag and drop files between two Nautilus windows, but if I try to drag a file from the network drive into an email for example, I get a popup about file permissions. Is it because flatpak apps don’t inherit my user permissions?
What protocol are you using? How are you mounting the drive?
The drive is NFS, on a Debian machine. I mounted it with a simple “mount” command into /mnt/