Are HTML and JavaScript files correctly served by your server? As in do you get any HTTP 404 errors? Are you using Pagespeed?

HTML are Javascript files are served correctly - we also run TYPO3 and Wordpress on the same web server. No 404 errors or any error in the php error log. We are not using pagespeed. We also disabled XCache, but that did not help.

Are you familiar with a browsers developer tools? Can you check in the developer tools to make sure there are all files served? Can you maybe also check if there is a JavaScript error? If not, can you maybe send us credentials to your Piwik installation to hello at piwik.org? View permission should be enough.

Thanks for the offer, the credentials where sent to hello at piwik.org

Thx for sending the credentials. It took me a while but I think the plugins are loaded in the wrong order. Can you open/edit the file config/config.ini.php and have a look if the [Plugins] sections starts with the following?

Plugins[] = CorePluginsAdmin
Plugins[] = CoreAdminHome
Plugins[] = CoreHome

If not, can you try to move them to the beginning or better try to bring your list of plugins in the same order as here https://github.com/piwik/piwik/blob/2.8.3/config/global.ini.php#L635 . If a plugin appears in the list of that file but not in yours just ignore it. Don't add any line, only move them.

BTW: I have recently created an issue for this see #6529 which would fix your issue in the future automatically but it is not done yet.

If it fixes your issue feel free to remove the account again

Awesome, thanks so much for debugging and solving the issue. It works flawless now.

To put these three as first plugins solved the issue.

Plugins[] = CorePluginsAdmin
Plugins[] = CoreAdminHome
Plugins[] = CoreHome

Thanks again and keep up the great work.

thx for letting us know! Glad it works now!