I tried to find any posts that talk about sms sending failure with Zorin connect but I didn't find why sms sending fails in some case ...
I've tried different combinaison of harware and android version but none of them had worked. I've also pay attention to disable firewall and set the sms application with default Android "Messages" app.
Is there any know bug or limitation to sms sending with zorin connect ?
It would appear that you have to use the terminal to send an SMS (appears not to have been sorted yet!), but you can reply to an SMS from the Desktop by hitting 'Reply' as in this article: