Authentication (and thus, installing anything) in Discover is either broken for all or for some users, for at least six months now.
For me, it either broke when upgrading to Byzantium, or with some update, maybe Q2 2022.
For reference: https://forums.puri.sm/t/kde-discover-no-authentication/17513
Can affected users run some tests, check permissions, config files?
Brand new installation and the bug is still present
Librem 14
OS downloaded from : https://downloads.puri.sm/byzantium/plasma/2023-06-14/pureos-10.3-plasma-live-20230614_amd64.checksums_sha256.txt
I found this related forum post https://forums.puri.sm/t/you-are-not-authorized-to-execute-that-function/19909/17
Can it be that PureOS still doesn't have the latest Plasma?