SKU scanner issues

I work at Ace Hardware store and we use the app 'Ace Retailer' to scan barcodes and SKUs.

I haven't had any issues using my two last iPhones, (13 pro and 14 pro), to scan bar codes or SKUs, either directly from any products or labels containing bar codes.

Since I got the iPhone 15 pro, I haven't been able to scan any barcodes.

What steps can I take to resolve this problem?

Thank you

Fernando