Why did I get result code 4?

The reasons PayPal returns this error code and possible solutions are:

• The amount being passed contains an invalid character or amount.
  • Check that the amount is formatted without commas or dollar signs ("1000.00" not "$1,000.00").
  • Ensure there are only two digits to the right of the decimal point. For example, "137.899" is incorrect. The correct format is "137.89" or "137.90" (if you're rounding up).
  • The address contains a period (for example, "Ave." or "Rd."). Delete the period and retry the transaction.
• A “0.00” authorization was submitted for a processor that doesn't support account verifications. Use "0.01" or "1.01" for account verifications as minimum amounts. Note: The minimum amount depends on the processor.
• The platform processing the transaction won't handle dollar amounts of up to 99999.99.
• The card-issuing bank wants to confirm the transaction. This is similar to result code 13.
• The customer's credit card has exceeded the spending limit.
• An amount larger than the original authorization cannot be captured. If a transaction exceeds the authorized amount, capture the original authorized amount and then submit another transaction for the additional amount. Due to security concerns, you must wait at least one minute to capture the original authorization after the failed attempt.

See also:
RESULT Values and RESPMSG Text