How to Fix wrong preview for link shared on FB?

First of All you need to see if you have properly mentioned Page Title, OG Tags If yes then It could be an issue because of Facebook Cache System. Facebook Cashe System store relavent information for links and use it where ever needed. In this way Facebook does not have to go again and again to the third party server for fetching data. All you need to do is refresh the Facebook Cashe for your link

Solution: Facebook Debug Tool

Go to the following link and submit your link and click Debug. It will refresh information stored for that link is Facebook Cache.

Facebook Debug Tool