Why Do Messages Get Blocked - And How To Fix Them

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TextPower Support
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When you attempt to send a message to a number and it is blocked there can be many different reasons why.  First, let's define the different types of blocking: 

  1. Blocked by the end user: End users can block text messages, either intentionally or unintentionally, for several reasons. 
    1. They subscribe to a cell phone plan that does not allow text messages.
    2. They subscribe to a cell phone plan that limits text messages to the amount allocated in a prepaid account.
    3. Text messages from short codes are intentionally blocked by the user upon request to the carrier.
  2. Blocked by the carrier: There are several reasons why a message might not be delivered to a phone number by the carrier.
    1. Carriers might have suspended service to a number if they have not paid their bill or have been sending messages containing illegal or illicit content.  Only the carrier can remove this suspension and only the end user can arrange it.  TextPower and you, our customer, have no influence or impact on a carrier suspension.
    2. There is a link in the message that has been created by a commercial link shortener such as Bit.ly, Owl.ly or others.  This can be easily remedied by using TextPower's own custom URL shortener.  Lengthy URLs can be shortened in our AlertManager application to a URL beginning with txts.cc/.  You have the option of a random link such as txts.cc/B2fo3hK4 or a custom link such as txts.cc/UtilityOutageReport.  You can create the custom portion of the shortened URL yourself as long as it is not already in use.  For details about this link-shortening capability read the FAQ about it HERE.
    3. The message contains a marketing message.  TextPower worked with the Federal Communications Commission several years ago to create a special "carve out" for utilities and municipalities that allows them to upload lists of numbers to be opted in to receive important or emergency information.  Marketing messages are specifically prohibited under this carve out and if the carrier detects that you are using your opt-in list to send such messages then can block any or all messages from being sent on that 10-digit code or short code. 
    4. The number that you're using to send text messages has not been "Sender Verified."  This is a new process initiated by the carriers just a couple of years ago that validates the number on which you are sending messages - whether your own number that we have text-enabled for you or a new number that we procured on your behalf - requiring TextPower to submit a special form to the carriers verifying who you, our customer, is and the purpose you are sending messages for on the 10-digit or short code.
    5. A "351" error indicating that the number to which the message was sent is invalid.  There are many reasons for this and a detailed FAQ about it HERE.
    6. If a STOP message was sent to a text-enabled 10-digit number instead of a QUIT message when opting out.  10-digit numbers work differently than short codes in that sending a message saying STOP blocks the number from receiving messages at the "network" level (i.e., the carrier).  This is why TextPower always recommends using QUIT instead of STOP; if someone texts STOP their messages to TextPower's system will be blocked until such time as they send UNSTOP.  More details about this type of blocking are in an FAQ HERE.
    7. Occasionally "porting" a number (moving it) from one carrier to another might result in a number being blocked.  It's rare but it does occur.  When that happens it can be easily resolved by having the user text your keyword to your short code or 10-digit code.  
  3. Blocked by TextPower: There are several reasons why TextPower might block a message from being sent to a number but the most common ones are:
    1. The number is not opted in and you are sending to a keyword on an opt-in account.  99% of accounts, excluding AlertDispatcher Pro accounts which use a phone book entry system, are opt-in accounts.  If a number is not opted in and you attempt to send a message to it you will see a notation in the logs in MessageReports reading "Not Sent: No Optin."  
    2. If a number has been opted out and you are attempting to send a message to it, even if you have set the "ForceOptin" parameter to "TRUE" in an API call, that message will be blocked. TextPower follows carrier compliance rules very carefully and once a number is opted it the only way messages can resume is if the end user texts the keyword into our system from their phone.  
    3. Your message includes characters that are not allowed in standard SMS messages.  We block messages that contain these characters - a list of which can be found HERE - before they get sent to the carrier.  This prevents you from being charged for the message without it being sent.  This often occurs when you attempt to copy text from a text editing application, such as Word, and paste it into the text entry field in AlertManager or an API call.  Some characters, such as a "smart" or "curly" quote or apostrophe, will cause the message to be blocked so we detect that at our end and stop the message from being sent.  
    4. The phone number has been blocked (blacklisted) by TextPower at the request of the end user or you, our customer.  We honor these requests from you or end users and if you attempt to send a message to a number that has been blacklisted it will be blocked until that number is removed from TextPower's blacklist.  Only TextPower can do this and only through a request to our support team (Support@TextPower.com).
    5. The agreed-upon number of messages sent to or received from a particular number in the specified period has been exceeded and the send has been blocked. This number is established in cooperation with you, our customer, at the initial stages of your account activation to prevent a rogue process on your end or an auto-reply loop set up by someone who has hacked their message app from generating thousands of messages.  If you have exceeded whatever number you set, for example 5/day or 20/week, during a testing period we can easily raise the limit or temporarily remove it.  But exceeding this limit will cause messages to or from any one number to be blocked.

As you can see there are many reasons that messages sent to certain numbers are blocked.  If you determine that a number is not receiving messages and is not subject to one of these reasons please contact our support team at Support@TextPower.com to get it resolved.