One-Page Checkout [Support Thread]

[lat9]

I am using The One-Page Checkout version number and release date: 1.0.5-beta1 (2016-09-xx)
on my 1.54 site on Responsive Sheffield Blue WWW.GELCANDLECOMPANY.COM. I've been having some customers tell me that they are unable to follow through the checkout and get a blank screen right after they enter c/c info info.
I tried placing an order on my desktop pc and noticed the CONFIRM button was displayed way on the far right which has been unable for some to see.
(see pic)
When some customers inform me of the trouble I inform that the button is at the far top right and they checkout successfully.

Is there any advice on how I can make the CONFIRM button appear in the center of the page making it more visible for desktop?
Mobile phones appear just fine.
Thanks for your input.

My apologies, but you're asking for help on an OPC version released 6 1/2 years ago (the current version's 2.4.5) and a version of Zen cart that was released 8+ years ago (2014-12-31).

The only help that I can provide (and I realize that it's not exactly hep) is that you need to upgrade your site so that you can make use of current versions of PHP (8.2 is the current as of this writing) as well as the current versions of Zen Cart (currently 1.5.8) and OPC.

The web's infrastructure regarding cookies and other security elements of a website have changed immensely over the past 6-8 years and I'll bet that those underlying changes and requirements are part of your issue.