MailChimp: Canadian Wireless Providers Blocking Two-Factor SMS Codes [u]


According to email marketing company MailChimp, Canadian wireless providers “began blocking Application-to-Person SMS messages,” as of November 10th.

The company says it is working with Canadian providers to resolve the issue, and in the meantime have disabled two-step logins asking for SMS authentication codes (customer 2FA discounts will remain in effect).

Screenshot 2017 11 13 10 32 59

Here’s what @RogersHelps responded to customers affected by this issue:

MailChimp says customers looking to secure their accounts can setup Google Authentication instead within security settings.

Two-factor authentication by SMS allows users to add a second layer of security when logging in, instead of just entering a password.

Are you being affected this carrier blocking of two-factor SMS authentication codes? We’ve reached out to carriers for comment and will update this post when we hear back.

Thanks David

Update Nov. 13, 1:11PM PDT: A Telus spokesperson responded via email to confirm “we do not block this type of SMS”.


  • Liam

    I have not been able to receive Dropbox verification texts on my personal, or any of our business accounts since Nov 3. Dropbox could not figure out why. Switched to Google Authenticator. I wonder if this is the reason.

  • I had a product launch slated for Nov 6 and I couldn’t login to my Mailchimp as of Nov 5 because the two-factor authentication sms was not coming through. Nice to learn why!!!

  • sukisszoze

    Same here, can’t get Dropbox verification text after upgrading to X…and I thought it was the Dropbox app not compatible with the X. Dropbox said everything is working on their end. Ended up switching to app based authentication.

  • Jay

    Am I the only one pleased about this? while execution wasn’t great I was tired of receiving 10 texts a month about various cruises or stupid promotions.

  • Now I know why I was not receiving my SMS from DropBox! I am on Rogers. The DropBox tech help had me turn off 2 factor so I could install login to DropBox on my new phone. I turned it back on but had to use my spouse’s Bell cellphone. What is going to happen when I try to login to my PayPal?

  • Bill___A

    Doesn’t appear as though Telus is blocking it. I just logged into Office 365 and paypal, received codes on both. I don’t use Rogers for that. However, in the past, there have been oddities with Rogers’ SMS as they used to get you to “approve” them one by one… who knows what is going on.

  • Update: a Telus spokesperson confirmed with us they do not block these SMS messages.

  • Bill___A

    Thank you, therefore I wonder why the headline is “Canadian Carriers” and not the specific one or ones. However I was able to add a Rogers phone to Paypal SMS today.

  • The headline was citing exact words from Mailchimp’s email.

  • Bill___A

    Valid point, but it spreads their misinformation.

  • ticky13

    No one should be using text messaging for 2FA to begin with as it is proven to be unsecure.

    An authenticator app is much more secure.