Can't install ownCloud from App Center



After going to Software > App Center > ownCloud > Install, I get this error:

An error occurred
Could not fulfill the request.

Server error message:

There is a problem with the certificate of the App Center server ([SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:581))

Can I please get some assistance on this? Any help (in English, please) would be greatly appreciated. Thank you!



my guess is that there’s a (transparent) proxy server in your network that scans all HTTPS traffic. If that’s the case, you’ll have to make your UCS server trust the CA certificate used by that proxy server. You can do that the usual Debian way:

  1. Place the CA certificate in the folder /usr/local/share/ca-certificates. Its format must be PEM, the file name extension must be .crt (this is important!).
  2. Now run update-ca-certificates. It should output something similar to this: 1 added, 0 removed; done.
  3. Verify that the call in 2 succeeded: there should be a symlink in /etc/ssl/certs pointing to the new file in /usr/local/share/ca-certificates.
  4. Try downloading a file manually, e.g. with curl > /dev/null ← this should not emit an error.

Kind regards,


Thanks for the response, mosu. But what does “update-ca-certificates ausführen” mean?



ignore that ausführen; it’s a leftover from me translating a German answer I gave to the same problem in a different thread. Just run the command update-ca-certificates.