To protect both consumers and businesses, industry regulators like the CTIA and wireless carriers hold the power to block messages from being delivered.

If you follow the basic rules...

...there's more than a good chance you'll never encounter any issues.

But to make sure you have the best understanding of what constitutes a "high-risk text," we'll explain some of the most common scenarios that result in a number or message getting blocked. Also, under the TCPA you’re not allowed to message anyone after they’ve revoked their consent to receive messages. So even if you received consent from someone in the past, be sure to immediately remove them as a recipient if they ask to stop receiving messages in order to maintain compliance.

If someone texts “STOP” to your number on our platform, they will be added to your Unsubscribed Contacts list and you will no longer be able to message them:

However, only you can manage do-not-text/call requests you receive in other ways.

First, we invite you to check out our guide to SMS compliance if you haven't already. It provides, in greater detail, the rules and regulations of text marketing.

Wireless carriers want to ensure the safety and security of their customers. Here are some messages they see as red flags.

SHAFT stands for sex, hate, alcohol, firearms, and tobacco. These five topics are considered high-risk due to their necessary age regulations (alcohol and tobacco) and the potential for driving illicit or illegal activity.

There are of course exceptions to the SHAFT rules. If you operate a bar, for example, you can still text with patrons as long as you operate on a dedicated toll-free number and institute an age gate to prevent anyone under the age of 21 from signing up for your texts.

Pornographic material, hate speech, or threatening messages are not tolerated and will result in a blocked number from carriers—and a permanent ban from SimpleTexting.

Many financial institutions utilize SMS. However, they never ask for personal information. Instead, they send out messages like text alerts for suspicious card activity, appointment reminders, and other harmless messages.

Text messages sharing high-risk financial investment tips are forbidden as well as information on loans and refinancing options. These messages aren't permitted by wireless carriers.

In addition to financial advice, carriers prohibit texts with links to donation sites. You can't direct people to external sites where they are asked to enter financial or billing information."

Bad apples who are phishing for passwords often use public link shorteners such as bit.ly. For this reason, we recommend our built-in link shortener. Carriers won't block your number and you'll be able to track clicks later. Win-win.

In order to add a layer of authenticity to any shortened URLs you do include, you'll want to go through a program like Rebrandly to ensure your domain is associated with the shortened link.

It can register as suspicious to carriers if you encourage recipients to reply to a number different from the one you texted them from (and keep in mind, to make sure you’re compliant with the TCPA, only send a message in the first place to recipients that have given express written consent to receive messages in response to a disclosure with the required terms—see our guide to compliance for help). Especially if your business uses a long code or toll-free number.

Always direct recipients to reply directly to the number associated with your SimpleTexting account. (Remember, all incoming SMS messages are free!)

With millions of texts exchanged daily, it's too hard for carriers to play big brother and manually read each message. Instead, they have a few systems in place that flag out-of-bounds content and will use their power to stop it.

Here are a few of the most common ways a carrier might discover, and subsequently block, your messages.

An abnormally high unsubscribe rate (relative to the size of the recipient list) can be an indicator of spam. Carriers are on the lookout for these spikes and use them as a way to flag suspicious activity.

[Read: 5 Tips to Keep Your Unsubscribe Rate as Low as Possible]

As we mentioned above, SHAFT content is generally related to high-risk text marketing. To get ahead of this, carriers set up filters to trigger alerts for content related to these or other inappropriate topics. The frequent appearance of words or phrases typically associated with these topics content can result in a ban.

In what we like to think of as a citizen's text arrest, anyone can report a message as spam. Simply forward the questionable message to 7726 (an FTC short code which spells out "spam"). While this doesn't automatically result in a block, it does notify carriers of suspicious or malicious content for review. If enough people report your message(s), it could result in a block number.

In the instance your messages have been blocked, you'll receive an automatic error message that looks something like this:

Error 50008: Message Delivery - Carrier Violation.

The best method to avoid being blocked is to proactively look into the rules and regulations of text marketing. The CTIA's most recent best practice guide is always available as well as any member of the SimpleTexting support team. We're happy to field questions on any messages before they're sent out.