Why is my online store's payment processing always resulting in an error?

[yeahlowdots]

Hello,

I was about to launch my online store and when I proceeded to a test payment, it turned out the payments all results in error. The payment provider page shows up, I can choose one of the payment methods, I can enter my payment information and once I click on the "validate the payment" button, it brings me back to the payment page with a single error message : " an error occurred during the payment processing, try again or chose a different payment method".

- I have tried 5 different payment method, same result.

- I  have checked with my payment provider : no problem on their end, demo payments work fine on their platform

- I have contacted Shopify : no problem coming from them

- I have tried uninstalling and reinstalling my payment provider app (kg inicis), I have made sure every Key and code matches.

- My currency matches the one of my payment provider.

- My delivery is all set.

- I made sure the vendor names on product matches the name that appears on the payment provider identification of my business.

- I have cleaned every cache and cleared every cookies.

I am desperate to understand what Is wrong so I can fix it asap.

Any insight would be greatly appreciated.