We are aware that there currently are some connection issues with the Silute server which may cause some of you to be unable to enter the world. The developers of the game also posted this message on the game’s website yesterday:
Also, a few of them are getting constant disconnections from the servers, and they are unable to play the game for more than a few minutes due to this issue. They are unable to connect to them, or they receive a message that says the server is full. Some players are encountering server issues while trying to connect to Tree of Savior servers.