There’s actually a run test script in the settings tab of WP-Piwik. Defining the user agent did help. But, finally got it to work by entering both of the following fields in WP-Piwik:
Piwik URL (REST API)
Piwik path (PHP API, beta)
The second blog is hosted on the same server.
How do I use the test script? The forum is in Deutsch.
Define my own user agent? You mean like add a new user? I’ve already tried adding a new user, but to no avail.