The guardian or groom said the wrong name or father's name during the contract. Is the contract valid?

If the intended spouse is clear and known to everyone present, and the witnesses understand who is being married, a small error in pronouncing a name does not invalidate the contract; but the officiant usually asks for the words to be repeated correctly to avoid doubt.
The conditions of the offer and acceptance are that it is clear who the spouse is, that it is continuous and understood (Sunan Abu Dawud 2085 on the guardian and witnesses). In the Shafi'i school, a clear identification, for example "this daughter of mine" with the bride present, can cover a mistake in the name. The problem is more serious if the guardian has more than one daughter and names the other, or if a different mahr is stated. If in doubt after the ceremony, ask the religious office; they may advise renewing the contract (tajdid). Check the spelling of names on the form before the contract. See a valid offer and acceptance.