Sometimes when I'm using my iPhone to message someone, their name appear as number instead of their name in the contact list. For example, I message to someone in my contact list named David. Instead of displaying "David" in the Messages app, it displays +84....... (his number). Sometimes this problem happens and it disappears after a a while and then it just come up again and disappear. How can I fix this.?I've updated the phone to IOS 14.7.1