I am finding multiple posts across Reddit, Facebook and this community about not being able to link Beatport streaming to Traktor 3 Pro (version 3.5.3 303). Unfortunately I am having the same issues (Windows 10). When I go to preferences -> streaming -> Beatport LINK -> login it forwards me to a https://api.beatport.com/v4/auth/login/?next=/v4/auth/o/authorize link. When I login nothing happens. I tried Chrome, Firefox and Edge without luck.
Would love to see some updates about this topic (just purchased the S4 MK3 to play with streaming.