You can set both the height and the width of the feed within the plugin settings which can be found by going to your WordPress Dashboard – Facebook Feed – Customize (tabbed page) – General (tabbed page) – you will find both height and width in the first two settings on the page.
Normally you would place 450px in the width setting and 450px in the height setting. However since you are putting a height restriction on the feed it is going to automatically add a scrollbar so you will need to set the feed’s width just a bit narrower to allow for the pixel width of the scrollbar within the total 450px box width you are placing the feed into.
If this is not working then please submit a support ticket here so we can dig deeper into the issue you are experiencing.
In the meantime, I hope your evening is going great.
