Many Thanks Juri, The quickfix works although it could not verify 2 signatures: gpg: key E1F958385BFE2B6E: 2 signatures not checked due to missing keys gpg: key E1F958385BFE2B6E: public key "X2go Debian/Ubuntu Packaging debian@x2go.org" imported gpg: Total number processed: 1 gpg: imported: 1 Do you think this can lead to a security issue due to the 2 signatures not checked? Best Regards, Saion On Wed, 28 Jul 2021 21:40:49 +0200 Juri Grabowski wrote: > Hello Saion, > > as a quickfix you can use another gpg server: > apt-key adv --recv-keys --keyserver keyserver.ubuntu.com E1F958385BFE2B6E > > On debian buster-backports and newer systems you can use extrepo: > apt install extrepo && extrepo enable x2go && apt-get update && apt-get install x2goserver > > I have changed this in wiki. > > Best Regards, > Juri Grabowski >