Simulation environment not loading

It seems to be that virtually every course I try to load won’t start… So far I have tried with " URDF for Robot Modeling" " ROS Basics in 5 Days (Python) Noetic" " Python 3 for Robotics Noetic" " ROS Basics in 5 Days (C++) Noetic"

The ‘loading’ icon on the black background continues to appear without being replaced by the actual simulation environment.

Vicenzo, are you using Chrome or Firefox? In case yes, can you disable any adblocker you may have?

Thank you for your answer. After an hour or so the system started to work, next time I will disable all the adblockers, thanks!