The cron syntax looks OK.
Would suggest running the command manually to see if there’s any errors when you execute it in real time, or sending the cron output to a log file of some sort for examination. There might be some feedback in mail messages if the system cron daemon is doing the normal internal e-mail notifications to the user whose cron job it is. I have never used the onboard Fax/SMS so not sure what else would go wrong once the command runs successfully locally, but from past experience working with Clickatell, Vonage, etc, there’s a lot of ways for SMS communications to fail even if the local server side processes execute normally.
One other thing to check, make sure that the CLI PHP is set to the expected version, e.g., you can have Apache running the module/plug-ins for say , PHP8.1, but the command line could be pointing at something different if there are multiple versions installed, which is pretty common on Ubuntu and other Debian based distros.