Facebook preview title does not change

I'm not entirely sure what you are referring to as the "Facebook preview title", but your form essentially has two titles you can choose.

1. The main title of your form, which you can set by simply clicking on the orange header inside our Form Builder:

This is the title that will appear as the name of your form inside JotForm.

2. There is the HTML title of your form, which appears when you open your form in its own browser tab. We call this the Page Title, and you can set it by opening your form's Preferences:

Once there, simply switch to the Advanced tab, click Show More, and edit the Page Title to your liking:

If you were experiencing issues with something else instead, please describe the exact issue you are having in more details, and we'll be glad to help out. Thank you.