Idea Cellular — Unable to send port message on 1900

I tried to send port message to 1900 from my idea number [protected] by using format port to port to jio. How ever the messages are not being sent, it shows sending failed. I have tested sending messages to other numbers and it works but messages sent to 1900 are being blocked. I have talked to idea customer care who repeatedly states that they couldnt find any reasons why port messages wouldnt be delivered. Please help