The following could be the reasons;
・ The card you are trying to use is not VISA, Mastercard, JCB or Amex, or has not been registered yet (Conditions apply for AMEX)
・ There is an error in the input contents (please enter in single-byte alphanumeric characters)
・ You are using a browser other than Chrome
・The card company you are using has restrictions on sending money overseas. (It is necessary to contact the card company to cancel the restrictions on overseas use.)
・ A deposit request exceeds the card limit. (Please check with your credit card company for the maximum amount.)
・ You've tried the procedure multiple times in a short period of time (it may take some time to stop at the credit card company)
・ If you use a debit card and the balance is exceeded