You cancelled on LinkedInNetworks says you didn't grant the permission, so nothing was connected. Nothing was saved on either side. Press Connect again whenever you want.
You took too longThe message says the connection took too long and expired, and to start again. The trip to LinkedIn is valid for ten minutes, so a tab left open needs a fresh start from the button.
The connection expiredNetworks tells you how many days are left and, at zero, that scheduled pieces won't go out. The way out is Reconnect, the same button as the first time.
The piece has more than twenty slidesThat is the document ceiling. The piece goes out through Download, which also gives you better resolution.
The LinkedIn caption is missingThe button stays disabled until it is written. You write it in the Publish dialog itself, with the 3000-character counter in view, and if the Instagram one exists there is a shortcut to borrow it and edit from there.
The tile says Coming soonThe connection is rolling out per account. Until yours is enabled, the piece goes out through Download: you get the images or the PDF and upload them yourself, with the caption already written on the piece.