Post Grid showing as a single column

Hi,

The posts on the Blog page used to work, but now are only showing as a single column. They used to display as 3 columns on a desktop/laptop which is what I want.

I've tried switching from 280px width to percentages (33%) as well as trying some CSS codes that were provided to other users with similar issues. Can't work it out...

The post grid I'm referring to is displayed on:

https://www.bethkarikari.com/blog/

[post_grid id="344"]

Theme used is Ultra Pro.

Any help you can provide is much appreciated.

Cheers