This might be either you have poor network coverage, or you might be having a service error. Check to see if service coverage is available in the area where you are. Check to see if signal bars, which indicate coverage, are displayed at the top of your screen. Text messages will not be sent if there is a service interruption or if the coverage is only one bar or less. Your service provider may also be responsible for repairing coverage faults.       Your SIM card provider's defects or errors are the cause of service failure. Due to a time-lapse from your service provider, you may see that the notification message blocking is enabled. To see if messaging services have been suspended by mistake, contact the appropriate customer service. Your message services may have been blocked or suspended by your service provider, resulting in the “message blocking is active” error.