Im a returning player, found I can't join the game due to this problem.
Firstly, i found out that im able to join Europe world only, this means Club world or other world that is in North America will make me "Failed To Connect". Then i asked my friend to login my account from his pc, which turned out it work and i asked him to bring my character back to Europe world which you can check with /region command.

Then i try to login and it worked. This might be different in your case, maybe you can join NA but not EU world. Try to use VPN which solve my problem. Or try to use your mobile hot spot, which also works for me. If you tried other wifi and no problem then just use a VPN to solve it.

- For some example
https://steamuserimages-a.akamaihd.net/ugc/2028347262933564446/ABD286935D7165F090FF4C91DCBA548496EEA23A/?imw=1200&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
This is Club world in North America, every time i join this world i get the problem before i found the solution.
https://steamuserimages-a.akamaihd.net/ugc/2028347262933565158/10E62C67E45E150A637D6256541C548BC6306B08/?imw=1200&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
This is Hub world in Europe, i can play like normal in Europe world but problem will occur once you join a North America world.

Try to launch the game on both server (Europe & North America)
- If one of the server can join means its your internet that made this problem(Try use VPN to solve).

Try using other wifi or internet
- If no problems, that mean your internet is somehow making the problem, just use VPN which solve the problem for me.

Try using other pc with same wifi
- If no problem then its your pc proble
- try these first and second method mentioned by supporter
- https://support.gamigo.com/hc/en-us/articles/203576518-Failed-to-connect-to-Auth-servers-

This link provide some method that might works
- https://support.gamigo.com/hc/en-us/articles/203576518-Failed-to-connect-to-Auth-servers-

If those not solving the problem, try to use VPN.