Twilo error in sending sms/ error 21408 in twilo

This is my code,to send sms via twilo!!

But i am getting this error! i checked my conf file thrice,and i find all to be correct! is there some fault with the generated number?
can somone tell me what does this error mean,i googled but could not undertsand!

no fault is being shown in the code!!.
and TO and FROM numbers are also correct!

Check for the SID and Auth_TOKEN number once again for uppercase and as well as lower case.

It looks like you have interchanged the From and To numbers so you do not have the permission to send the message to that number as the account is from India. Make sure that the ‘From’ and ‘to’ numbers are written correctly.

I would suggest you to check the “” file if the token number, api, device id are correct. Else check your twilo account if the “from” number is correct and in “to” enter the number in which you want to receive the sms. It seems you have entered the from number in to.

I rectified the error,the error was not in the conf file,but was in the actual code! Interchanging the words in the variable sms(line 8)!! TO_NUMBER should be prior FROM_NUMBER and because of this, error was being shown, so yea,order of writing in these variables matters!
Thank you all,for your help!