Welcome to the community!
I'm sorry to hear you're having issues with your service. Could you please provide some additional information? Did you recently activate a new account? What phone are you using -- was it purchased in Canada or abroad? Have you been able to previously send/receive texts? Are you unable to send both SMS and MMS? Are you able to make/receive calls?...
Have you verified the phone has the correct short message service centre (SMSC) number: +1-514-993-1123
Sorry for all of the questions, but the additional information would help determine the issue.
**edit** Are there certain locations outdoors where you are unable to send texts? Are there other outdoor areas where you are able to send texts? Could you have been outside of coverage when you're having issues?**
Welcome to the Community!
I just wanted to give you a little heads up that I had to modify your message as it displayed personal information in a public forum.
I'm sorry to see you're experiencing issues with your messaging, can you tell us if you had the chance to reboot the phone? Did you notice any improvement after the reboot?
Also, can you let us know how many signal bars you have on the screen when you are trying to send these messages?