Answered question
I have a data only plan, but I decided to try the Call and Text add-ons. The calling works fine and I can still receive texts, but when I send I first got "error 21" and now after following some of the troubleshooting steps here, I get an "incorrect phone format" error. I have tried all the recommendations (other than let it resolve itself) with no success.
verify the APN setting and also the texting app that you are using if there is any setting in the app for APN. If you are using a 3rd party texting app, some app have the APN setting inside the app.
Other answers
Hummm have you checked all your APN settings?
Other than that you'll have to chat with CS here https://fizz.ca/en/faq/resolving-issues
Chizz :))
Were you sending using contact list ? If so please try to enter a phone number instead to see .
What number do you have in settings for SMS service centre? It should be +14385200092.