need a link to that page. there is just a ad landing page when clicking the link. not the same page in your screen capture.

sorry the link is CClubs | Just another WordPress site

It seems your page doesn't load.

Anyway, identify the culprit (which element is the border being applied to) and edit its CSS, either removing the border declaration or making it border:none;.

But I quite like the border, it gives the content a boundary. I'd just make it white/transparent.

I've checked with 3 different browsers and don't see a border.

Hey,

Your link doesn't show your site, anyway you have to take a css for your main-content {border:0px solid} in your custom css.

Thanks

You can Inspect Element of Google Chorome check class of image then you login wp => Appearance => Editor => style.css => Ctrl + F and edit it

You can use Dream Viewer.
Dream viewer is he software that checks the error and provide you both graphic site and source code. It will be helpful for your need.