We are facing the issue again that Toolset Debug info is empty when certain plugins are activated. The last time we had this the WordFence plugin was the culprit. This time round it appears to be the WPML Multilingual CMS plugin. When it is activated the Toolset Debug Info become empty.
I've seen a few other users had similar issues due to the use of some Umlaut characters in the German language (Ä, ä, Ö, ö, Ü, ü). Our site is in English and German.
I wasn't able to reproduce this, even though I added German to my site and created a post type using Umlauts in its name and translated some content and added lots of Umlauts to the content and taxonomy translations.
Are you able to isolate the cause any further? Do any of your plugins or your theme use Umlauts in their names, for example?
Does the problem occur if you only have Types and WPML active?
I played around a little and activated the plugins one by one again. Now it works fine with WPML but not with WordFence again. I think WordFence could be blocking some kind of request. The last time we had this problem on our last ticket, WordFence was the culprit, but as in my original ticket it was WPML this time that was not playing ball.
I'm not sure why WPML is now working but WordFence not again. What is happening when we go to Toolset > Settings > Debug ?