In October 2016 the CTIA and cell phone carriers started cracking down on what they refer to as 'spam texting'. If they detect your Campaign as possible spam they can place a temporary block on your number. That block can last from 5 mins to an hour depending on the severity of it.
Unfortunately we don't have any control or the ability to remove those blocks. If this happens you can still receive all of your inbound messages and you should be unblocked within the hour.
The good news is that you can drastically reduce the chance of your Campaign being flagged for potential text spamming by avoiding the following:
Carrier's spam filters look for large sizes of SMS blasts to block so we've limited the maximum amount of candidates to be in a text campaign to 50. By keeping the Campaign to 50 candidates the success rate of a completed Campaign is much higher.
Keep the average length of your campaign text messages to 2 texts or less. We include a text counter so that you can stay within the guidelines (remember - emojis use up a lot of character space so consider using emoticons instead :) )
Over use of weblinks or email messages (don't include them in every Rectxt campaign that you launch).
EXCESSIVE ALL CAPS, punctuation and special characters such as 'Hi how are YOU???????'
Avoid using an excessive amounts of phone numbers in your Campaign message.
Finally - make sure the message content is always relevant and appropriate.
At the end of the day, use your common sense when launching text campaigns, and if you're even unsure about the message then always err on the side of caution.