Can you reproduce this on our demo: http://demo.piwik.org/index.php?module=CoreHome&action=index&idSite=32&period=day&date=yesterday#/module=Actions&action=menuGetExitPageUrls&idSite=32&period=day&date=yesterday ?

Well when clicking on your link I got only index-sites.

And even if I select the whole week there only one site in each group:

So if I manually go to demo.piwik.org and select a list of sites I can't fold it at all. The option just is not there:

Okay, finally I got a table with more entries and it works there:

Is it possible that you create an account with view access to your Piwik installation so we can debug? If so, please send us credentials to "hello at piwik.org" and comment here afterwards (just in case it goes to spam folder). You could delete the account directly after we had a look again

We will discuss this. I will let you know if I know more.

Mail sent from r*.k******@outlook.com.

We also had error messages obviously caused my nginx pagespeed, but they does not seem to have anything to do with this issue.

Any news here? Did you had a look into our installation?

I just had a look and it seems to be caused by page-speed probably see eg #5081 (comment). Can you try to disable it?

For more technical users: Something adds a <head/> element to the XHR request but the request should not return a <head/> element but start with a <tr/> element.

Also possible that this is done by another extension.

We will look into it again.
I thought Pagespeed was already disabled, but probably it was just the CSS-Pagespeed part.

Okay, so yes, it was Pagespeed.

So we have disabled it and it worked. However we don't want to disable it for the whole site.
As we have Piwik installed in a subfolder on our domain (and not in subdomain) we tried 'ModPagespeedDisallow' but it did not worked. So does this only work with subdomains or didn't we configured it correctly?

We're using nginx with Plesk 12.

I mean as we use nginx we tried it with pagespeed Disallow "*/piwik/*"; but that does not work either.

Sorry we cannot give pagespeed support here. If someone knows the answer please comment here. Feel free to ask in the forum as well ( http://forum.piwik.org/ ) there might be some more users that can help you. Will close the issue as actual problem is resolved