Getting empty response

Hi,

i'm trying to set up the connection to your API so that i can convert a web page to a pdf, for the test purposes for now. Unfortunately i wasn't able to use you conversion library for java, project is running on OSGI and it has some dependency errors, so i went with custom code. But for some reason i'm getting the empty response with the 200 code. Obviously i'm missing something, could you please check if something pops up to you, cuz after spending some hours on this i'm running out of ideas. here is the code:

The same config works fine in Postman.

Thanks in advance!

BR,
Valeriy