The login trouble has been resolved. Organization Owners and guests should be able to sign in with email addresses and passwords once again. We're sorry for the interruption to your workflow and we appreciate you bearing with us while we worked on a fix.
11:28 PM PST
It looks like we're out of the woods, but we are still monitoring the situation to be sure. Thank you for your patience.
11:13 PM PST
We've identified a potential cause and we're digging in to possible solutions.
10:43 PM PST
We are investigating an issue where some Organization Owners and guests are unable to log in to Slack using their email address and password. We apologize for the disruption.
10:10 PM PST