Schedule once, then read the status
The useful part of a scheduler is the status after you leave the screen.
States
A job is queued, sending, published, failed or waiting for a new login. Partial success names the networks that did not go out.
Reconnect
If the network rejects the token at publish time, the account becomes needs reauth. A background check is only a backup. The post activity log records the change.
Where to look
The post page lists each target. The calendar shows the scheduled time in the workspace timezone. The inbox lists failures and accounts that need a new login. It does not invent direct messages the networks have not sent.