Access to a social account expires eventually, and until now you found out when something failed to publish.
If a channel loses its connection you now get a dialog the next time you are in the workspace, listing which ones are affected with a Reconnect button on each. Most take you straight into the platform and back to where you were. Mastodon needs its instance URL, so it sends you to your channel settings.
It stays out of the way after you dismiss it, and comes back if a different channel breaks.
Also this week
The timezone picker is now searchable, with your own timezone suggested at the top. It is the same picker in the schedule header, your posting schedule, and the composer, so it behaves the same everywhere.