Sending one-time password by SMS directly to a phone number

Question

I use AWS SES to send one-time passwords via email. I am implementing the same via SMS with AWS SNS.

I created a topic, otp, and manually added the phone number to it as a subscription.

The following code works both locally and on the server:

      var params = {
        // TODO: fix this.
        //PhoneNumber: "+351914...",
        TopicArn: "arn:aws:sns:...:...:otp",
        Message: "Your code is..."
      }
      var publish_text_promise = new AWS.SNS({apiVersion: '2010-03-31', profile_name: "sms"}).publish(params).promise();

      // Handle promise's fulfilled/rejected states
      publish_text_promise.then(
        function(data) {
          console.log("Message sent: %o", params);
          console.log("MessageID is " + data.MessageId);
        }).catch(
          function(err) {
            console.error("Error in sending OTP by SMS");
            console.error(err, err.stack);
          });

I would like to send directly to the phone number, so it does not require manual intervention and I can add other users on the same topic. When I add PhoneNumber instead of TopicArn, it sometimes works, and sometimes I get this message:

InvalidParameter: Invalid parameter: PhoneNumber Reason: +351914... is not valid to publish to

The phone number is correctly formatted: when I tested it locally, it always worked.

I have the same code locally and remotely and the same AWS credentials file as well.

Why does the code work locally and sometimes fail remotely? How can I send directly to phone numbers?

Answer 1

The issue was an invisible character in the phone number, which you can see after the 6:

InvalidParameter: Invalid parameter: PhoneNumber Reason: +3519...6‬ is not valid to publish to

I had cleaned the phone number before adding to Contacts on macOS, but it seems that Contacts adds these characters here and there. The character disappeared when I removed the phone number. Because the character was at the end, I missed it when I selected the phone number to copy-and-paste.

Following the comments, one solution to debug this issue is to try the AWS SNS console.

Therefore, this thread is closely related to this thread:

This was definitely caused by an encoding issue, paste the code below into jsfiddle, and mouseover to see the warning on the first plus sign which reads:

This character may get silently deleted by one or more browsers