So, looks like client issue. I'll leave this open as a request to handle better such situations, i.e. to not even try to connect to SMTP and return better error.

Got it going!

The apache access log is telling me:

Reading source code I see only one case when simplexml_import_dom()'s argument can be NULL here. It is when php://input stream is empty. (feof() returns true). https://git.kolab.org/diffusion/S/browse/master/lib/ext/Syncroton/Server.php;e0fb77d4c05c95cc78dc8c9b38517b8a84d5a40e$130. So, the problem may not be in the php code.

Its possible that I made a mistake in my config. Kinda hard to debug.

BTW, iOS 7.1.2 with kolabnow.com account works for me.

...but I agree that if empty body (for whatever reason) is detected it should not even try to connect to SMTP server.

Of course I added my recipients-adress also. Forgot to mention that. Its a normal adress with alphabetical letters and .org ending.

Jeroen, the warning on simplexml_import_dom() indicates the problem is on activesync protocol level.

Would just putting "test" in the subject and body not mean an empty recipient list though?

I will do my best to provide this, if you tell me how.

I was more interested in the request body on activesync/http protocol level.

Normal text (just tried by just putting "Test" as subject and "Test" as content).

The error tells us that the activesync request body is missing or syncroton faild to parse it.
So, to track this down we'd need to know what exactly was sent by the device.

This seems to occur with https://git.kolab.org/T1023 already applied.