Why it matters
After a domain sale, the buyer points the name to a new site, and propagation decides how fast people see it. The delay is usually minutes to a few hours, and it depends on the TTL set on the old record. Sellers and buyers can lower the TTL a day before the switch to cut the wait. Do not call it a failure when some visitors still see the old site. Common mistake: making repeated edits during propagation, which makes it hard to tell what is live. Check with a DNS lookup tool, not a browser, since browsers cache too.
Source: cloudflare.com
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