Hello Adel! Welcome to the forum.
Please clarify whether you are currently trying to run Simlink on Catalina or Big Sur? Your title suggests you’re running Catalina, and your description suggests Big Sur.
If you’re running macOS Big Sur, please read this post: macOS 11 Big Sur: Simlink Hangs, X-Plane Cannot Launch - #22 by skysail
Regards,
Malte