On 22.01.16 15:12, Clemens Klein-Robbenhaar wrote:
 some random ideas:
   - in WEB-INF/xwiki.properties: are any settings for extension.repositories=...  enabled
     or are they all commented? 
They are all commented
There are only the following - commented - settings:
$ grep extension\.repositories xwiki.properties
# 
extension.repositories=privatemavenid:maven:http://host.com/private/maven/
# extension.repositories.privatemavenid.auth.user=someuser
# extension.repositories.privatemavenid.auth.password=thepassword
# extension.repositories=local:maven:file://${sys:user.home}/.m2/repository
#
extension.repositories=maven-xwiki-snapshot:maven:http://nexus.xwiki.org/ne…
#
extension.repositories=maven-xwiki:maven:http://nexus.xwiki.org/nexus/conte…
#
extension.repositories=extensions.xwiki.org:xwiki:http://extensions.xwiki.o…
# extension.repositories=
$
I will try with uncommenting the two proposed defaults next week.
      If I uncomment just a lone
'extension.repositories=' I get exactly the error in the screenshot
   - Another idea: any chance there is a name resolution problem on the server?
      
extensions.xwiki.org should resolve to 5.135.240.206 (currently) 
works fine:
$ host 
extensions.xwiki.org
extensions.xwiki.org has address 5.135.240.206
$
       "curl 
http://extensions.xwiki.org"
-> should return a 302 to the Start page 
fine, too:
$ curl 
http://extensions.xwiki.org
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>302 Found</title>
</head><body>
<h1>Found</h1>
<p>The document has moved <a
href="http://extensions.xwiki.org/xwiki/bin/view/Main/WebHome">…
</body></html>
$
frank