It turns out many players are failing to connect outside of DDOS and hang at authentication due to DNS issues. If you're still having trouble connecting to Octo please try this solution.
Navigate to C:\Windows\System32\drivers\etc and edit the hosts.txt with admin notepad to include:
185.165.170.59 normal.octowow.st
This should fix the issue.
Source: r/u/Firm-Environment-253 · by /u/Firm-Environment-253