[Freeswitch-users] debian-unstable on Stretch

[Stanislav Sinyagin]

I'm trying to install the unstable FreeSWITCH on debian Stretch, and I
get the following error:

# apt-get update
Hit:1 http://security.debian.org stretch/updates InRelease
Get:3 http://files.freeswitch.org/repo/deb/debian-unstable stretch
InRelease [4,595 B]
Ign:2 http://cdn-fastly.deb.debian.org/debian stretch InRelease
Hit:4 http://cdn-fastly.deb.debian.org/debian stretch Release
Ign:3 http://files.freeswitch.org/repo/deb/debian-unstable stretch InRelease
Fetched 4,595 B in 1s (3,266 B/s)
Reading package lists... Done
W: GPG error: http://files.freeswitch.org/repo/deb/debian-unstable
stretch InRelease: The following signatures were invalid:
20B06EE621AB150D40F6079FD76EDC7725E010CF
W: The repository
'http://files.freeswitch.org/repo/deb/debian-unstable stretch
InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore
potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user
configuration details.

I imported all public keys that I could find, but it didn't help.
Which key was used for signing this repo?