[SOLVED] Error importing Release.key - Kopano / apt not working

Hi,
I got a serial for Kopano (using it with Univention 4.4). I recognized that (when doing apt-get update) there are some errors regarding all kopano repos, telling me:

Fehl:71 https://download.kopano.io/supported/webapp:/final/Univention_4.3  InRelease
  Die folgenden Signaturen waren ungültig: EXPKEYSIG 5CB27E1358E2F2A7 Kopano Development <development@kopano.io>
Fehl:109 https://download.kopano.io/supported/files:/final/Univention_4.3  InRelease
  Die folgenden Signaturen waren ungültig: EXPKEYSIG 5CB27E1358E2F2A7 Kopano Development <development@kopano.io>
Fehl:123 https://download.kopano.io/supported/mdm:/final/Univention_4.3  InRelease
  Die folgenden Signaturen waren ungültig: EXPKEYSIG 5CB27E1358E2F2A7 Kopano Development <development@kopano.io>
Fehl:154 https://download.kopano.io/supported/smime:/final/Univention_4.3  InRelease
  Die folgenden Signaturen waren ungültig: EXPKEYSIG 5CB27E1358E2F2A7 Kopano Development <development@kopano.io>
Paketlisten werden gelesen... Fertig
W: GPG-Fehler: https://download.kopano.io/supported/webapp:/final/Univention_4.3  InRelease: Die folgenden Signaturen waren ungültig: EXPKEYSIG 5CB27E1358E2F2A7 Kopano Development <development@kopano.io>

When I try to import new signatures with e.g:

wget https://download.kopano.io/supported/webapp:/final/Univention_4_3/Release.key

It tells me: Unauthorized.

If I combine it with my User serial and the number it also does not work.

So can you please tell me how to import the updated kopano release-keys, to get apt working again?

As you saw, I am running UCS 4.4. Is the repo (4.3) for Kopano correct?

Thanks a lot!

SOLVED: It seems like something strange was going on yesterday, when importing the Release.key. I tried it again today:

wget https://serial:serialnumber@download.kopano.io/supported/smime:/final/Univention_4.3/Release.key

and it worked.

I am getting old, maybe “I” happened yesterday…