The common explanations.
YOU CHANGED IT IN THE WRONG PLACE
If your nameservers point at Cloudflare or another provider, cPanel records are ignored.
The most common cause by a wide margin.
CACHING
Resolvers holding the old answer. Wait, or check the authoritative servers directly.
YOUR OWN DEVICE
Browsers and operating systems cache DNS independently.
Try a private window, another browser, and mobile data.
A CONFLICTING RECORD
A CNAME cannot coexist with other records for the same name. Adding one where an A record exists produces unpredictable behaviour.
THE TTL WAS LONG
A record with a day-long TTL takes a day to expire everywhere.
THE CHANGE WAS NOT SAVED
Check it is actually present in the zone.
HOW TO DIAGNOSE
Query your authoritative nameservers directly. If they return the new value, the change is made.
Then it is caching, and waiting is the answer.
