Troubleshooting registration of international numbers with Duo


Duo can use international numbers, but there are cases where they may not work or may need to be set up a certain way. 

Possible Solutions

Make sure the number is properly formatted

You can enter your international phone number with the E.164 format: + (plus sign), then country code (1-3 digits), the national destination code (or area code) and subscriber number. If you have a leading 0 in your international number, it may need to be removed to properly format the phone number. 

For example: The country code for the United Kingdom is +44 and the number locally is 07911-123456. This would result in the following number: +44 7911 123456, due to removing the leading 0. 

Try setting up your device as a landline

If your desired device is a mobile device, try to set it up as a landline instead of a mobile phone to see if you're able to add the number that way. Please note that this will restrict you to phone calls only on this method, if successful.

Some countries are considered unreliable for phone calls with Duo; please review Duo's list of supported countries to see if your country falls into this category. 

Try setting up your mobile smartphone as a tablet

Alternatively, if your desired device is a smart device, try to set it up as a tablet instead to be able to use the Duo Mobile app for pushes and passcodes. The instructions to do this will be almost the same as our iOS registration guide and our Android registration guide, however, please select Tablet instead of Mobile phone when prompted to select the type of device being registered. 

Consider using a token

While this will not fix issues with an international phone number, it's another method to authenticate that will work for a majority of counties. Please refer to our article Using Duo while traveling internationally for more details about using Duo in an embargoed country.

For more information about tokens, you can read our About hardware tokens for Duo article. If it may be some time before you can get a token, you can also request a bypass code to authenticate in the meantime. 


Article ID: 136538
Thu 8/5/21 11:22 AM
Sat 9/2/23 2:27 PM

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