SOLUTION: Thank you very much @skydriver5709 and @EV1LGENERAL for your recommendations! I was able to solve the problem by going to Settings > General > Online tab, and from there I turned off “Aircraft Traffic Type”, “Air Traffic in career”, “Live Weather” and “Multiplayer”. I save the changes and exited the Settings page, then went back to Settings > General > Online tab, and turned back on all the settings that were turned off (“Aircraft Traffic Type”, “Air Traffic in career”, “Live Weather” and “Multiplayer”). That solved the problem for me.
Found and got my missions back!
Special thanks to the guy who created the video where I found the solution: NoLinga on Youtube.
His video with the solution on the chat search for on youtube: NOW SOLVED: Cargo Transport or VIP Missions Not Loading | Microsoft Flight Simulator 2024