1. The token expired
LinkedIn access tokens have set lifespans. When one lapses, every scheduled post after it fails until the account is reconnected. Fix: reconnect in your scheduler. A tool that tracks token age can prompt the reconnect before anything depends on it, which is how this stops being a problem at all.
2. Your Page role changed
Publishing to a Company Page requires an admin role held by the connected member. Agencies lose posts this way constantly: a client tidies up their Page admins, removes a name they do not recognise, and the schedule dies silently. Fix: confirm your role on the Page itself, restore it, reconnect. Then make Page roles part of your onboarding checklist so it cannot recur unnoticed.
3. The media broke a spec
Videos outside the accepted length, size or format bounce at publish time, and image posts have their own limits. The current LinkedIn spec sheet is linked below; the usual fix is a re export to MP4 with H.264 at a moderate bitrate.
4. API limits
LinkedIn limits publishing volume per member and per Page. Bulk scheduling months of content into a tight window can trip it. Space the queue and stagger multi client publishing across the hour rather than on the hour.
The pattern behind all four
Every cause here is invisible until publish time, which is exactly the problem. SocialPro monitors connection health continuously, checks each post against the current specs before its slot, confirms delivery with LinkedIn afterwards, and alerts you instantly in plain English with a one tap retry when anything fails. For an agency, that is the difference between managing publishing and hoping about it.