Short Code Text being Blocked

[packleft]

My bank in the US is suggesting that my Canadian mobile carrier is blocking the receipt of a verification text due to a short code block. Does this sound feasible, and if so, how can I request to have my bank short-code whitelisted?

[packleft]

Good to know. Thank you for the deeper insight - it all makes sense.

I managed to get the bank to switch on email 2FA for me instead.

[softech · Accepted solution]

@packleft 

A bit more details to the situation, as why the US 2FA came before but stopped working:

Some U.S. banks’ 2FA SMS "sneak" into  Canada because the bank or its messaging provider uses an SMS aggregator (e.g., Twilio, Sinch, Syniverse, Infobip, etc.) that has an established interconnection/routing path with Canadian carriers such as TELUS/PM. Although the U.S. short code was not be intended for Canadian use, the message can still be delivered through that international/aggregator route if the Canadian carrier accepts it. This also means that if a bank changes its SMS aggregator or delivery route, the new provider may use a different route or have different Canadian carrier support/filtering, which can cause 2FA messages that previously worked in Canada to suddenly stop arriving.  So, it is really not Public Mobile actively blocking it, but a setup on the senders (US bank in your case)

[packleft]

Okay thanks.

I was receiving the text messages until around January this year, then they stopped. I do not see my bank in the list in the short program offerings.

Also, this bank is not sophisticated enough to offer an alternate means, even though I immediately revert to my 2FA authentication app over text, as soon as any service offers it. I have many, but not for this bank.

I still find it odd, that the short codes would stop working, or if they changed their short code, that it would not resolve in the +1 country code across all dialling codes.

[softech]

@packleft 

It is not unusual for not receiving 2FA text from overseas as they use shortcut.  International shortcode text, like 2FA text from US banks, are not guaranteed., it is a hit or miss. Regular international text are ok but not shortcodes.  It might work on some providers sometime and experience show it will broke sometime 

only Canadian shortcode text found here are guaranteed 
https://www.txt.ca/en/current-short-code-programs/

So, it is better to check with your overseas bank and see if you can receive the 2FA using other ways, such as email or authenticator app