problem with 4g modem

[Frank68]

Hello

I asked for the 4g modem to be installed in the reactor, since a customer has only provided me with 4g sim, when the APN returns and the internet connects, I send the emails but I have an error in sending the SMS.
Does the SMS library also have to be modified in order to manage the new modem?

  below the error reported in the offending lines

Code:

function sendsms(number, message)
  require('socket')
  client = socket.udp()
  client:sendto(number .. ' ' .. message, '127.0.0.1', 12535)
end