Why Some Services Won't Text Virtual Numbers

You type your number into a signup form and click "send code." Nothing arrives. You click "resend." Still nothing. No error, no bounce, no explanation. The service says the code was sent; somewhere between their fraud checks and the carrier network, it was dropped.

If you use a virtual number, this scene is familiar. Here's what's happening behind that form, why services do it, and how to avoid getting burned by it.

What happens when you click "send code"

Phone numbers carry metadata. Before sending anything, many services run your number through a lookup that returns the carrier and the line type: mobile, landline, or VoIP. Virtual numbers, Tether's included, usually show up as VoIP or non-fixed lines in these databases.

The service then makes a choice: send the code, refuse with an error, or accept your number and quietly never send anything. The silent option is the most common and the most maddening, because you can't tell a blocked number from a delayed text.

Some services layer fraud scoring on top. Your number gets a risk score based on line type, carrier reputation, how recently it was issued, and how many accounts it has been seen on. High score, no code.

Why services block virtual numbers

Fraud, almost entirely.

Free disposable-SMS websites publish numbers anyone can use. Fraudsters use them to create accounts by the thousand: fake social profiles, abused signup credits, manipulated reviews. A phone number is supposed to be evidence that one human sits behind an account. Disposable numbers broke that assumption.

So platforms reached for a blunt tool: block anything classified as VoIP. It stops the disposable-number farms. It also stops expats, nomads, and everyone else with a legitimate reason to hold a number that lives in the cloud.

Financial services have an extra reason. Regulators expect them to verify identity, and a number tied to a physical SIM and a billing address reads as stronger evidence than one that isn't. That's why the blocks you do run into are more likely to come from a bank than a social app.

Why the same number works one month and fails the next

Compatibility shifts constantly:

• Fraud vendors update their rules and reclassify entire number ranges.
• A service tightens its filters after an abuse wave, then quietly relaxes them.
• Some services block VoIP at signup but accept it for login codes on existing accounts, or the reverse.

Treat any compatibility list, including ours, as a living snapshot rather than a guarantee.

What we've tested

We keep a running service compatibility list based on real usage of Tether numbers. The short version, as of this writing:

• Most banks we've tested work. Capital One, Wealthsimple, and Wise all deliver codes. Wells Fargo blocks virtual numbers, and some customers have gotten a block like that lifted with a support call.
• Most big platforms work. Amazon, Facebook, Instagram, WhatsApp, and ChatGPT all deliver codes to Tether numbers. Claude.ai blocks them.
• Government services can work. The Canada Revenue Agency delivers codes to Tether numbers.
• Airlines have a clean record so far. Air Canada, Cathay Pacific, Delta, and United all work.
• Telegram verification doesn't work. Telegram's signup codes don't arrive on Tether numbers. Verify Telegram with a different number.

Real mobile numbers are coming

Every block described above traces back to the same root: the VoIP classification. A number that looks like a regular SIM to carrier databases is far less likely to trip these filters.

That's what we're building next. Tether is working on real mobile numbers with stronger support for login codes and account verification. Leave your email and we'll let you know when they're ready:

How to protect yourself

Test before you depend. While your old number still works, add the virtual number to a critical service and trigger a real code. Five minutes of testing beats discovering a block from another country.

Prefer authenticator apps. Where a service offers app-based 2FA, take it. Those codes are generated on your device, so there's no delivery step for anyone to block. SMS becomes your fallback instead of your single point of failure.

Save backup codes. Most services hand out one-time backup codes when you set up 2FA. Store them in your password manager. They work when nothing else does.

For banks, ask. If your bank blocks the number, a call to support sometimes gets the restriction lifted. Failing that, most banks offer authenticator apps or in-app approval.

Recheck before big changes. About to cancel your last physical SIM? Run through your critical services again first. A service that worked at signup can tighten later.

Where this leaves virtual numbers

For most services, most of the time, virtual numbers work fine. The blocks are concentrated in banking and a handful of platforms, and they're avoidable if you know about them upfront. The failure mode to avoid is surprise: finding out about a block when you're locked out and the code will never come.

That's why we publish the compatibility list instead of promising everything works. Check it against the services you depend on, test the important ones, and keep an authenticator app as your first line of defense for anything critical.