https://techcrunch.com/2020/05/22/spacexs-first-crewed-spacecraft-launch-is-officially-cleared-to-proceed-on-may-27/

SpaceX has received approval on its mission to launch NASA astronauts for the first time ever on May 27, having passed the final Flight Readiness Review (FRR) conduced by the agency to ensure everything is go for launch.

This final check, conducted over the past few days after the Crew Dragon spacecraft was mounted on top of the Falcon 9 rocket that will take it to the International Space Station (ISS), has officially concluded and the result is that everything is cleared to go forward with preparations ahead of the launch on Wednesday.