Understanding Carrier Filtering/Blocking

It’s crucial to your SMS marketing strategy that you have a strong grasp on how spam filtering and carrier blocks work within the texting ecosystem. It can be confusing and maddening and I want to try and take some of that confusion away and provide you with some helpful tips.

We have to understand that the carriers own their networks. It means that if Carrier A doesn’t want particular traffic on their network, they can decide to block it. For many of us, we assume the text messages that we send to our recipients automatically reach their destination because we have a relationship with that recipient and they haven’t requested me to stop texting them. While that is a component of deliverability, it’s not the only one. Texting is a best attempt delivery channel much like email. A sent message is not guaranteed to be delivered to the end destination (a phone in the texting example). Why? How can that be?

When you send a text message, that message goes through a number of “hops” before it ultimately reaches its final destination. I like to think of texting similar to writing a handwritten letter and putting it in the mailbox. Here are the “hops” in you writing that letter:

1. You place the mail in the mailbox and lift the red flag alerting the mail carrier you have a letter to be picked up.
2. The mail carrier takes your letter out of the mailbox and places it in the mail truck.
3. The mail carrier delivers your letter to the local post office for transport to a processing plant. It may be transported via many modalities including trucks, planes, etc.
4. At the processing plant, your mail is sorted by destination, size, etc and is then sent to the next processing plant. Your letter may be delivered to multiple processing plants on its journey to the final processing plant of your recipient.
5. The mail is transported from the recipient’s processing center to the local post office.
6. The recipient’s mail carrier places the letter in the recipient’s mailbox.

Now, when we write our letter and place it in the mailbox the only thing we can be sure of is that our local mail carrier picked the letter up out of our mailbox. We have no indication or receipt of the letter making it to the local post office, successfully traveled to the recipient locale, was delivered to the recipient’s local post office, or ultimately placed in the recipient’s mailbox.

Texting is very similar in how your message is handed off many times before it ultimately is delivered to your recipient’s phone. Multiple contracted parties touch your mail. You may not know this but your mail, when on a flight to a processing facility may be on a FedEx, UPS, DHL, or even military flight! Yup, the USPS contracts with third parties to move the mail around.

Texting is very similar to this process. When you schedule your message in Project Broadcast it’s similar to our step #1 above. You know the message is scheduled and Project Broadcast will let you know if it was successfully able to take your message and deliver it to the next “hop” in the carrier network. If an error occurs (and is reported back) in our attempt to get your message to the next hop, we display that error to you. Once it leaves Project Broadcast’s system it can go through many other 3rd party hands including other intermediate carriers and spam filters before ultimately being handed off to your recipient’s carrier. Even then the recipient carrier will have its own filtering that may occur.

So what is a carrier block? Well, it’s complicated! Because there are multiple hops in the network you may have a block at any one of those hops. Blocks also can be channel-dependent. Meaning, you may be blocked on the MMS channel but not the SMS channel.  You may also have a block that is not permanent. Some blocks are temporary and can last 24hrs, 48hrs, 7 days, etc. Generally speaking, a block just means that somewhere in the carrier network you have been prevented from delivering text messages to that carrier’s customers either temporarily or permanently. It is also possible you are not blocked, it’s just that your content is being filtered.

Here are a few reasons why you may have your text messages filtered or your number blocked:

1. Content:
   1. If your content is considered spam or is unwanted traffic (for example CBD, SHAFT, Payday Loans, CryptoCurrency, Debt Relief, Gambling, Raffles, etc) it will be filtered and potentially result in a block. There is a large list of topics carriers don’t want on their networks. These are just some examples. Even trying to include something like a publicly shortened URL (bitly, tinyurl, etc) can trip spam filters.
2. Missing identity:
   1. Every text message is measured on its own merit. A commercial text message being blasted out without you clearly identifying yourself is likely to be filtered and ultimately may result in a block.
3. Missing Opt-Out:
   1. A commercial text message being blasted out without clear opt-out language is likely to be filtered and ultimately may result in a block.
4. Stops:
   1. If you receive too many stops in a given time you will get blocked. For many carriers, the threshold is 1%. If you send 1000 text messages in a bulk message and get 10+ stops you could get filtered and ultimately blocked.
5. Reported As Junk:
   1. Even though a recipient may not reply “stop”, they have the option on their phone to report a text message as junk. That is sent back to the carriers as feedback from their customers on the quality of messages. If you receive too many junk reports from your recipients you will also be filtered and potentially blocked.
6. Media:
   1. Your media (images) can also cause blocks to occur. Many spam filters in the network also look at media and may flag a particular graphic as spam. If you are using the same graphic as other senders, it’s possible your text messages are filtered because the graphic itself was flagged as spam due to another sender in the network. 

Also, false positives can occur! For example, let’s say you send out a text message to a list offering a fun Bingo game to get engagement with your audience. Well, guess what? That message may be determined as gambling (due to the Bingo wording) and be filtered due to its content.  

What should you do to make sure you have the highest deliverability possible?  

When sending a message that is commercial in nature, especially when being sent as a mass message, you should always include 1) who you are and 2) a clear call to action for the recipient to opt-out.

You should also ONLY send messages to the recipients who have consented to you specifically sending them that message. Failure to properly segment your recipients to only those that have explicitly asked for your message creates a high risk of your messages either being replied to with stops or being reported as junk. As mentioned above, stops and junk reports will cause your messages to be filtered and ultimately may result in a block.  

I am often asked: “Do I have to include opt-out language in every message?”. In conversational messaging, no. However, when sending commercial messages (messages about your product, sale, promotion, etc) absolutely! Every message is measured on its own merit. The spam filters have no knowledge of your previous messages sent to a recipient. Meaning, let’s say you sent out a commercial message last month and did include an opt-out but just sent a new message this month and did not include it. The spam filters will inspect your message and make the determination that you have not included any opt-out language in the message and start filtering your messages. Ultimately, it may result in a block. It is also very possible that on the same carrier, some recipients get your message and some don’t. This could be due to a few things including the fact that spam filtering isn’t done by a single master server somewhere. Your messages may hit multiple servers running filtering and a particular server has now identified your message as spam while others have yet to do so. Additionally, some messages may have been delivered before a threshold was met by the filtering systems.

So you think you have a block… now what? The first thing to do is inspect your recent messaging. It is possible that the message you are seeing now as filtered/blocked was not the original culprit that got you filtered/blocked!  

1. If you look at your recent messaging, did it clearly identify who you are?  
2. Does your message contain a clear call to action for the person to opt-out?
3. Did you send your message to only the audience that consented to receiving it?
4. Does it include media that may have been used by another sender?

You should re-attempt your message making sure that all the above items are in place. If you re-attempt your message and are still getting poor deliverability, you can reach out to our support team for assistance. 

In order for Project Broadcast to help investigate your potential block you’ll want to gather a recent example (last 24hrs) of a message you know for certain was not delivered to a recipient. You can email us at support@projectbroadcast.com with both the message and recipient info and we can look at your account and try to help track down the cause of the block and attempt to get you unblocked. 

It is possible that when we investigate your particular case our systems show your message was successfully handed off downstream with no issue. There are cases when your messages are not delivered that are not related to blocks or filtering. A message may not be delivered if a phone is out of service or out of coverage, the device is on Do Not Disturb, carrier congestion is present, network outages in the texting network, etc. In some cases, carriers will re-attempt delivery to a phone but there are also carriers that do not retry delivery. These same reasons can also cause text messages to sometimes be delayed when delivered. Ever sent a text message to a friend to find out that it was delivered hours after you sent it? That same thing can happen with platforms like Project Broadcast. Once a message is placed in the carrier network we are at the mercy of all the players in the ecosystem to get that message to the recipient’s phone.

Another thing I’ll touch on here is that just because you are not getting responses from your recipients, it doesn’t mean they are not being delivered. If you are primarily using Project Broadcast to blast out promos, coupons, etc., you’ll find your response rate will drop off over time. Put yourself in the place of the recipient. Let’s say you received a promo message each month from the same sender. You may respond to the first message but very quickly you’ll train yourself to know that the sender only sends you sales/promos/coupons. As you get new text messages from that sender you will subconsciously stop reading their messages unless you have a buying motive. Yes, Project Broadcast can be used to send out a mass promo message but the power of Project Broadcast is to create engagement and manage many active conversations at once. Find ways to add value and connect with your audience so that messages that are commercial (sales, promos, etc) are not the primary messages your recipients get. However, there are also strategies you can deploy to see how your messages are engaged such as using trackable links and landing pages for your commercial content. Ultimately, when you do send out that commercial message you follow the strategies above!

Even with these challenges, texting remains the best form of personal communication due to its high read rates and filtering compared to other channels. Don’t let this info discourage you because now you know what to look for and how to craft messages that are more likely to be delivered!