Invalid signature in the Ubuntu 20.04 repository

I have tried today installing nsigh-systems from the repository at and the signature Release.gpg is invalid (this is what apt-get says and I have also checked it manually with gpg).

I am sorry that there was no response to this earlier, your forum post was dropped in an orphaned category that the Nsys team was unaware of until this afternoon.

Can you try again with the more recent drop?