I am using Joplin 2.7.15 (prod, linux) on LMDE 4 (I installed the desktop-application very easily with the Linux Mint Software Manager) and I get an "Failed to generate PDF" error when I try to export all my notes to a PDF.
I am not using the snap version. However this issue has been reported about 1 1/2 years ago for the snap-package and I'm not sure about if it has been fixed yet.
For Joplin to become an real alternative to Google Keep, etc. for me, I really need a feature that allows me to export multiple notes into one document (preferably sorted by tag).
Not 100% sure if it is the same for the Debian version but the LM store usually lists the Flatpak distribution for install (which is community maintained, not an official release) and the sandboxing does occasionally cause issues unless you alter the permissions manually or with flatseal. You also need to handle the updating differently.
This really seemed to be an sandboxing issue.
I opened Joplin using the official AppImage (./Joplin-2.7.15.AppImage --no-sandbox) and managed to export selected notes into multiple PDFs.
Google Keep exports notes with same tags into one single document, which I find more handy. But I'll give it a try. I think the "Combine notes" plugin will help.
Users could manually grant permission for the snap to print. In the next few weeks, there's going to be a fix that means they won't even need to grant manual permission to print, it'll just work due to new security mechanisms in snap around printing support. Tl;Dr, there's now a
cups snap, and it'll proxy between the host CUPS server and snaps who are trying to access CUPS. If your system didn't even have CUPS to begin with, then the CUPS snap will actually provide printing support for all the apps on your computer, not just snaps.
I'm not entirely sure with Flatpaks but I'm under the impression they should be able to print if you grant them permission to access the CUPS socket.
In theory Electron can also fix the problem for all Flatpaks/Snaps by changing their printing backend to use the XDG Desktop Portals printing portal.