3DS (3-D Secure) is the cardholder verification mechanism that Visa, MasterCard and other card networks use for online payments. Visa brands it as Visa Secure. It confirms at checkout that the person paying is the cardholder, which cuts down fraud; after a successful check, liability usually shifts from the merchant to the card issuer.
It commonly fires on a first bind or new subscription, a large amount or repeated charges in a short window, a region that requires strong customer authentication (for example the European Economic Area), a billing address or exit IP that does not match the usual environment, or a small pre-authorization before the real charge.
Each check incurs an account verification / authorization fee (in-app: 3D Secure verification fee). For the amount, the two tiers, and why the bill may show 0.04 USDT, see What is the account verification / authorization fee (3D Secure verification fee)?.
Please note that 3DS verification is usually initiated by the merchant during checkout, not set by the cardholder. You cannot turn 3DS on or off in the MPChat App.
How to complete 3DS verification
Where is the verification code sent?
When a merchant triggers 3DS, the one-time code is sent to both of these channels:
Your MPChat registered email — the email you used to create the MPChat account. Check inbox and spam/junk.
In-app notification — open the MPChat App and check Notifications / inbox.
Both channels carry the same code. Enter it once; either channel is enough.
If you don't receive the code
Wait 1–2 minutes; delivery can be delayed.
Check both the registered email (including spam) and the MPChat App notification list. Don't rely on only one channel.
Confirm the email on your MPChat account is current and is the mailbox you are looking at.
Do not tap pay repeatedly. Multiple 3DS challenges in a short window are more likely to fail.
If neither channel arrives, contact MPChat support from the App. Never share your CVV or full card number.
Note
If no verification page appears at all, the merchant may not have initiated 3DS, or this transaction may be below their challenge threshold. Confirm with the merchant first, then contact MPChat support.