There has been major confusion over how Djokovic was given an exemption to enter the country, without having disclosed his vaccination status. Tennis Australia gave him the exemption after it was cleared by two medical panels, but the Australian governments rules are different and therefore Djokovic, a nine-time Australian Open champion was not allowed to enter the country and his visa was revoked.

from Times of India https://timesofindia.indiatimes.com/sports/tennis/australian-open/full-timeline-of-novak-djokovics-australian-visa-controversy-so-far/articleshow/88807724.cms