This is a problem that appears from time to time with major Android updates. If you are still dealing with this problem on your Samsung mobile, you can apply some temporary solutions that have worked for some users.
One of the first options you have to check is that “Show info. Call ”is active. You will find this option in Settings >> Other call settings. And if the problem is that it does not show you the name of your contacts when you call, then try deactivating the option "Caller ID and Antispam", which you will find in Call settings.
This is one of the most used functions, since it prevents unknown numbers from becoming a nuisance, but for some reason it creates conflict by preventing it from identifying the number of the contacts.