Read this page as a quick path: scan the headings, use the step blocks, and escalate if the expected result does not happen.
Standard syncs (under 1,000 contacts) typically complete within up to 30 minutes.
For larger syncs — over 1,000 contacts — allow up to 12 hours for the sync to fully complete. This is normal and does not indicate a problem.
You can monitor progress in the Referrers tab, which will populate with new records as the sync processes. If the tab shows no new contacts after 12 hours for a large sync, check your integration settings and confirm the connection is still active.