Find and Replace Question

I keep running into an issue when using the find and replace function. Sometimes it works, sometimes it doesn't, and when the find and replace doesn't work, the pop up notification says "it's possible the data you're trying to replace is in a protected sheet. Excel can't replace data in protected sheets". However, I've checked the info tab and the access is unrestricted, and I've checked the Review tab and the sheet has never been protected when this occurs. Can you please help in diagnosing the problem I keep having?

Thanks!