Why do I get this error "Remote Transaction Failure. Please Contact Support." ?

Hi there,

This error also occurs to me. I keep getting this error message: "Remote Transaction Failure. Please Contact Support.". I was able to make one test-purchase where the purchase went through, then I wanted to test it again but then I got this error and I didn't change anything in between.

Can you please help me out here.

Thanks and regards,
Allan