It's slightly different depending on the app.
Error running action: plinth..install(app_id="tor", packages=["tor", "tor-geoipdb", "obfs4proxy"], skip_recommends=false, force_configuration=null, reinstall=false, force_missing_configuration=false): RuntimeError("Apt command failed with return code: 100")
Stdout:
│ freedombox set on hold.
Stderr:
║ Initialized apps - apache, api, names, avahi, storage, backups, cockpit, firewall, config, datetime, diagnostics, dynamicdns, first_boot, help, letsencrypt, networks, power, privacy, security, snapshot, ssh, sso, upgrades, users, bepasty, bind, calibre, coturn, deluge, ejabberd, email, featherwiki, gitweb, gnome, ikiwiki, infinoted, janus, jsxc, kiwix, matrixsynapse, mediawiki, minetest, minidlna, miniflux, mumble, nextcloud, openvpn, pagekite, performance, privoxy, quassel, radicale, roundcube, rssbridge, samba, searx, shaarli, shadowsocks, shadowsocksserver, sharing, sogo, syncthing, tiddlywiki, tor, torproxy, transmission, ttrss, wireguard, wordpress, zoph
║ E: Failed to fetch http://deb.debian.org/debian/pool/main/o/obfs4proxy/obfs4proxy_0.0.14-1%2bb4_armhf.deb Temporary failure resolving 'deb.debian.org'
║ E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/t/tor/tor_0.4.7.16-1_armhf.deb Temporary failure resolving 'deb.debian.org'
║ E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/t/tor/tor-geoipdb_0.4.7.16-1_all.deb Temporary failure resolving 'deb.debian.org'
║ E: Failed to fetch http://deb.debian.org/debian/pool/main/t/torsocks/torsocks_2.4.0-1_armhf.deb Temporary failure resolving 'deb.debian.org'
║ E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
Action traceback:
╞ File "/usr/lib/python3/dist-packages/plinth/actions.py", line 398, in _privileged_call
╞ return_values = func(*arguments['args'], **arguments['kwargs'])
╞ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
╞ File "/usr/lib/python3/dist-packages/plinth/privileged/packages.py", line 70, in install