Short codes are the five- and six-digit numbers that banks, apps and delivery services text from. They travel over the same networks as ordinary texts but through a separate approval system, so a phone can exchange messages with friends all day and still get nothing from a short code. The checks below run from the quickest to the most involved.
Start with the program
Confirm the number first. A single wrong digit sends a keyword to a different program or to nothing at all. Then make sure the program is still running: codes are leased for set terms, and a campaign that has ended leaves its number silent.
Think back to whether the phone ever texted STOP to that code. Industry rules require a program to stop all messages after an opt-out, and it stays stopped until the subscriber texts the program’s keyword again. Some services use START for this; Venmo, for one, tells users to text START to 86753 when its codes stop arriving.
Text HELP to the code
Every short code program has to answer HELP with its name and a way to reach customer care, under the monitoring handbook the carriers audit against. So HELP makes a clean test. A reply means messages from that code can reach the phone, and the problem lies with the specific alert or sign-up. No reply means the block is somewhere on the path.
Next, text HELP to a different short code, preferably one run by a large organization. If that one answers, the phone and account can handle short codes and the first program is probably at fault. If neither answers, the trouble is on the subscriber’s side.
Check the phone
Phones can block short codes like any other sender. AT&T’s messaging help points to the blocked contacts list in the phone’s settings and to the message app’s own block list, and notes that a phone with full storage can stop taking in messages. Restarting the phone after clearing space costs nothing.
Check the account
Carriers let account holders block premium or short code messages on a line, and parental controls on family plans can do the same. Such a block is easy to forget, since ordinary texts keep working. Only the account holder can have it lifted, usually with a call to customer service asking for short code messaging to be turned on.
Numbers moved from one carrier to another cause a quieter version of the same problem. The handbook requires a subscriber who ports a number to opt in again, and until that happens a program’s messages may not arrive.
Two situations cause trouble whatever the account settings say. U.S. short codes work only on U.S. networks, so a phone on a foreign SIM card cannot reach them, and a U.S. phone roaming abroad often cannot either. Numbers from internet calling apps are the other case: they receive short code texts from some programs and not others, and some banks refuse to send codes to them at all.
When only one code fails
If other codes answer and one does not, the fault is the program’s. The quickest fix is usually through the sender’s own website or app, which may offer email or a voice call instead of a text. When a program ignores HELP or STOP altogether, the Short Code Registry, which leases the codes on behalf of the industry, takes reports about codes that are not following the rules.