If settlement fails when using the POS machine of a Huawei mobile phone to swipe a credit card, there may be several reasons:

1. The credit card information is incorrect: First, you need to confirm the credit card information. **, validity period, CVV code and other information are entered correctly. If there is an error, you need to re-enter it.

2. Insufficient bank card balance: Make sure there is sufficient balance in the credit card account. If the balance is insufficient, the card swiping will fail.

3. Network connection problems: Unstable Internet connection or poor signal may also cause transaction failure. It is recommended to check the network status and signal strength and confirm whether you are connected to a reliable network.

4. Bank card restriction issues: Some bank cards may have consumption restrictions when using them, such as the daily limit on the amount of card swipes. You need to check the specific consumption limits of your bank card.

If you have tried all the above methods and still cannot settle successfully, it is recommended to contact the credit card issuer or call Alipay or UnionPay customer service for more specific help.