are you able to open your TeamPulse trial through a browser (no Test Studio involvement) freely? Usually this sort of issue occurs when there's a problem with the TeamPulse instance and communication cannot be established.
I suspect that if you wait it out for a few minutes you will eventually see an error message informing you that connection could not be established.
Keep in mind that TeamPulse is a stand-alone app that is access through the browser. Test Studio doesn't server as a "gateway" to TeamPulse.
Also, keep in mind that you will need to have created a Project and have established acceptance criteria in order to connect to TeamPulse. You can only connect to an established project in TeamPulse - not with the TeamPulse app itself. Make sure you have an existing Acceptance Criteria in your project before you attempt to connect:
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