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?
Not sure if this is related or not but when I was unable to open media files (that were stored on my SMB server) in VLC (also got permission denied) I solved it by installing “kio-fuse”.
Hope you figure it out.
Thank you – Flatseal fixed the problem!