If you are experiencing problems while testing your iSMS or other SMS deployment, here are a few things to consider:

1 - carrier incompatibilities

Mobile carriers around the world, and particularly in developing countries, may not be using standard software or protocols.  This can affect the ability to transmit SMS messages to and from mobile devices using those carriers. The only way to determine an incompatibility is to test your iSMS or structured SMS or messaging implementation using mobile devices from those carriers. Testing is essential before committing to a deployment, and should be done well in advance.

2 - character incompatibilities

If you find that some of your SMS messages are not being received, it may be that you are using some characters that are not supported by the destination carrier (i.e. the carrier of the person who is supposed to receive the SMS message).  Some local carriers, for example, only support the GSM character set, instead of the larger UCS2 character set. Read more.

You can test to see if any characters in your message are not GSM-compatible by using a free GSM character checker, like the one here.

3 - restarting your iSMS session

If you wish to end all current iSMS sessions for your phone:

  1. Send 'EXIT' or 'EXIT ALL' to the server. This will End all pending  iSMS sessions and allow you to start new one.
  2. After EXITING from sessions, initiate another iSMS session from your online form by removing the number and then adding it over again in the interactive SMS menu.