Available Test Items field is empty

Thank you for your prompt answer! I’ve watched the videos and went through the unit test section thoroughly and learned new things, however the initial issue hasn’t been solved. I created a new, blank project with only the sample tests in it and tried to execute those cases but the situation is the same. I can see the configured sample test items but that is just because there is a test configuration xml by default in the working directory. Once I delete the xml file, I cannot retrieve them. I also tried configuring Opc Ua, changed TCP port number and tried to reload available test items with the new configuration… unsuccessfully.