Spam texts are not only annoying. They can cost you money and increase the possibility of scams.
The bad news is that this problem is growing. One reason is the availability of affordable, unlimited texting plans. Another is low-cost, disposable phones.
The good news is that many cell phone providers (carriers such as AT&T, Verizon, etc) have implemented content or spam filtering in order to protect their subscribers. These carriers are continually working to block spam texts. Unfortunately, spammers are very good at getting around the blocking technology. Learn more about carrier filtering.
To protect yourself as much as possible, do not interact with the spam messages. Do not visit their links. Do not respond to any of their offers. Know that these 'free offers' are usually phishing scams whose goals are to steal your personal data.
On the flip side, it could happen that your message was flagged as objectionable by the carrier--even if it wasn't really.
You are sending large amounts of picture/MMS messages from the same number.
Your users complained to their carrier that they were receiving unwanted messages.
Carriers are filtering you based on content (objectionable keywords or links) e.g. http http:// https:// https bit.ly goo.gl TinyURL.com Ow.ly Is.gd Buff.ly AdF.ly Bit.do Mcaf.ee and so many more. Also, know that the word 'gift' along with a $ looks spammy to the content checking programs. We recommend using rebrandly.com. See Solutions (below).
Carriers are filtering you because the volume of messages you are sending from each standard long code phone number it too large. We recommend secondary numbers. See solutions below.
You are sending similar or identical content from a long code to many multiple numbers within a short period time. We recommend secondary numbers. See solutions below.
Your messages have been caught by the carrier filter for some unknown reason. Carriers do not advertise how their spam filters work to avoid reverse engineering.
Be sure you have a good user experience and clear opt-out instructions.
Avoid sending questionable content. See which types of messages count as questionable content.
Send fewer messages from each long code. For example, in the US you should adjust your message send rate so it is more consistent with typical human operation per CTIA's guideline in Messaging Principles and Best Practices. The CTIA advises that each long code phone number should stay under 15-60 messages per minute and under 200 unique recipients a day. Use additional secondary numbers.
Wait a period of time before sending messages again. When most carriers blacklist numbers they have a cooling off period before they can send again.