Confirm Button Not Displaying When Using Salemaker

Had some inventory in a clearance section with Salemaker. That worked fine for several months, but when I added another sale for all other items, the confirm button does not show for customers.
I tried resetting the sale ( both sales) and sometimes it works when original sale is on,but other is not sometimes it doesn’t. Do I need to adjust sale settings in some way? Trying to clear out inventory and customers can’t complete order.
Site is 123scrapwithme.com
Version 1.5.1
Afraid to update site at this time because I am not that computer savvy and don’t want to mess it up. I inherited the site from previous owner.

Any advice or work around greatly appreciated.

The confirm button to which you refer... what where?

While having provided the site designation, can you help lead a little more with some specifics of for what anyone would be looking?

As to the various sales, is this a situation where a category was put on sale and then tried to apply a sale to everything in the store? Or as I read the description: sale on one category, applied a sale to every other category.

There may be some other issue involved as well, what version of php is the site seeing? (admin screen, upper right corner is a version link and the php version should be listed in the upper portion of the window.)

To prepare for the upgrade, recommend reading:
http://www.zen-cart.com/entry.php?3-How-do-I-rebuild-my-site-on-the-new-version-instead-of-upgrading

Yes, sale is one category, the applied sale to every other category.
I’m talking about the confirm order button (pg 3 of check out) that should be at bottom of page.
Only thing in upper right corner it says:
“New Version Available v1.5.6a :: v156a contains updates for PHP 7.2 and 7.3
Download Here
(You are presently using: v1.5.1)”
If I keep the one category sale, conform button is present. If I have both sales or the second sale (all of pf store except for one category) th confirm button is not present.
Thanks for link about prepping for upgrade. I read it, still is beyond me...