Test an alternate network such as a mobile hotspot to determine whether the problem is isolated to your current network.More information on troubleshooting security applications here, if curious. Fully update or temporarily uninstall security programs which may be interfering with your connection to the server(s).
Try the following to narrow this down further:
This can have many potential causes ranging from corrupted local files to a network-related problem. Thanks for reaching out! Getting stuck at the title / Lion Doors usually indicates that your game client couldn’t connect to the game server.