This warning means CoSchedule couldn't read the preview image from the web page your Facebook message links to. It can happen on any plan.
What the error says
The warning shows in yellow. While CoSchedule is still trying to send the message, it reads:
An error occured when sending this message, CoSchedule will attempt to send this message again throughout the next several minutes. Facebook Open Graph data did not match the message. We will re-scrape and try again.
Why it happens
Open Graph data is the information on a web page that sets the title and image of its link preview. When CoSchedule can't read the image from it, you see this warning as a precaution. The message usually still publishes.
Fix it
- Check the linked page with Meta's Sharing Debugger to see what's missing.
- Add or fix the page's Open Graph data on your website.
- If the message failed, reschedule it. If it already published, don't reschedule it, or it will publish again.
While the warning is yellow, CoSchedule is still trying. Don't reschedule it yet.