+CMS ERROR: 304

[fazelmojiri]

on: modem.sms()
give error : +CMS ERROR: 304

why???

[websharik]

304. Invalid PDU mode parameter. Error sending message. Invalid PDU format.

You may be sending a message to your phone in the format +7-xxx-xxx-xxxx. Remove the plus in front of the phone number. It is also possible that your mobile operator requires that the first digit of the number is eight: 8-xxx-xxx-xxxx.

[chander-git]

thanks, @LionG2 now it's working