The High Cost of Anonymity: Why Banks Block Virtual Numbers
To comply with UK and European regulations (including Strong Customer Authentication (SCA) and PSD2), Stripe and regulated banks (such as Monzo, Revolut, Barclays, or HSBC) must verify the legitimacy of account signups.
Because VoIP (Voice over IP) platforms do not require identity checks to assign numbers, they are a primary vector for identity theft, tax fraud, and credit scams. Financial fraud algorithms check the carrier type database of every number entered. If the number falls in a block range assigned to a software routing provider (like Google Voice, OpenPhone, Twilio, or Zoom Phone), it is immediately blocked.
The HLR Handshake: Signalling Tier 1 vs Software Routing
Standard virtual numbers exist strictly on the software layer. When Stripe triggers a 2FA text, it queries the Home Location Register (HLR) database. This lookup matches the target IMSI range to check the MNC (Mobile Network Code). Real SIMs have a hardware-associated MNC signaling directly with standard GSM switching exchanges. VoIP numbers fail this check because they map to virtual softswitches, indicating a missing physical device layer.
Secure Your Business 2FA
SecondSim eSIMs route natively over standard UK mobile carrier towers, ensuring 100% verification success on Stripe, banks, and payment gateways.
How to Resolve Bank Verification Blocks
1
Perform a VoIP Verification Check
Perform a VoIP Verification Check
Verify if your current number is classified as VoIP. Use our VoIP Verification Checker. If the carrier check returns a software or landline flag, the number must be swapped for compliance.
2
Activate a Carrier-Native eSIM
Activate a Carrier-Native eSIM
Instead of carrying another physical device, get a digital eSIM from SecondSim. Our eSIMs assign a real UK mobile number registered under Tier-1 carrier network codes, allowing you to run two active lines on one device (Dual SIM) securely.
3
Re-verify the Financial App
Re-verify the Financial App
With the eSIM active on your phone, resubmit the verification code request. The incoming SMS OTP will be processed instantly by your phone's native dialer, securely passing the banking verification checks.
KYC Compliance Check Breakdown
| Verification Check | Standard VoIP Services | SecondSim Carrier eSIM |
|---|---|---|
| Stripe KYC Registration | ❌ Mismatched Carrier Flag (Blocked) | ✅ Verified (MNC Verified) |
| Monzo / Revolut 2FA | ❌ Fails SCA Protocol | ✅ Authorized |
| Physical SIM Card Required | No | No (Digital Setup) |
| HMRC Tax Expense Eligible | Vague (Often blended accounts) | Yes (Dedicated corporate line) |