I asked that because when you click in the invite link from the website it's showing in MAINTENANCE
Is that okay?
There's some problem with a redirect from their web page. Go straight to the slack channel:
https://myhush.slack.comSlack invites have been disabled due to security problems on slack. Basically someone can steal someones Identity - it's possible to create account with the same nickname. This problem is in slack code so everyone is waiting for them to fix it as it touches every 'group'.