The issue affecting multiple features, including file uploads, message edits, and channel management, has been resolved. A fix has been fully deployed, and all systems are functioning normally. If you are still experiencing any trouble, please perform a hard reload of Slack by pressing Command + Shift + R (Mac) or Ctrl + Shift + R (Windows/Linux). Mobile users should fully close and relaunch the app.  We sincerely apologize for the disruption to your day and appreciate your patience while we worked to sort this out.