There are some reasons why someone cannot text on their phone. The first reason is that the person may not have a texting plan with their cell phone service provider. Customers must have a texting plan added to their service to send texts. The second reason someone cannot text is if they have used up all their allotted texts for the month. Once customers have reached their monthly limit, they must purchase more texts or wait until the next billing cycle to start fresh. Finally, someone may be unable to text if their phone is incompatible with texting services. If a phone is too old or uses an outdated operating system, it may not be able to receive or send texts.