Credit Card.
There are a couple of reasons why you can experience payment troubles.
Important note! If your bank has canceled a payment for reasons that are unknown yet, please do not try to repeat a purchase before the reason of the failure is determined. This can lead to multiple charges or fund holds.

First, reach out to your bank and check the following:

Technical problems. Ask for the reasons for a failed payment – it can simply be caused by technical problems on their side. When you made sure that the payment failed, try to conduct the transaction once again
Payment limit. Some credit cards or banks establish a limit for Internet payments. Contact a bank representative to know why the payment has been denied.
Low balance. Insufficient balance often comes as an unpleasant surprise. In case of a failed transaction, double-check your account to make sure you have enough funds.
Incorrect personal information. You may have entered an incorrect personal info by mistake, and the payment was declined, as the data you have given us did not match that on the credit card. Also, make sure your card is not expired.
Fraud detection. This sometimes happens when you are already browsing under a VPN. An unusual IP address or address from a different country than that of your credit card can sometimes cause this, but such occurrences are very rare.

If you have eliminated all of the reasons mentioned above, but still have troubles paying, contact our support team via [email protected] describing your situation.

PayPal.
PayPal payment troubles are mainly the same as the credit card ones. These are the two most frequent ones:
Technical issues. Check what find of checkout you chose – PayPal Express Checkout or the Standard one. It’s better to use the option you have used previously.
Insufficient balance. Again, the problem can be as simple as a low account balance.

If you have check this points and everything is okay, please contact our support team to receive all necessary assistance.

BitCoin. There are two main problems with BitCoin payments:
Long processing time. Due to the nature of this currency, Bitcoin transactions can sometimes take a long time. Before you waste your nerves, check the Bitcoin mempool first and see where your transaction is.
Invoice expiry. Maybe the invoice had expired by the moment you made the payment. In this case, contact our support team using a convenient method (live chat, ticket system or email [email protected]).