There was an issue processing your payment. Try again or use a different payment method. What's this

[FancyThings]

I am getting this error when I try a test payment on my own store:

There was an issue processing your payment. Try again or use a different payment method.

Can anyone help me with this? Thank you.

I don't know.

[Retail-King]

Hey FancyThings 

Shopify Payments won't work if the gateway is in test mode so that could be throwing things off. Are you able to test with a cash payment? Let me know some more details and I can try to help you out here! 

-iain