Thanks for your post and welcome to our community.
Very sorry you're having some issues with the new SIM in your handset, this isn't good.
It certainly sounds like the phone is locked or not compatible with the new SIM.
I can help so I'll pop you a personal message to grab some details and get the ball rolling 🙂
I have a Nokia 1616 and the same problem with the new SIM - the dreaded "SIM not valid" message. The unlock code on the letter that came with the new SIM did not work so I have used up one of my three chances to unlock. I have tried the text messaging service but both I and they are really just going round in circles.
Are you aware that there is a second thread on this community reporting the same problem?
I eventually called 789 and waited long enough to speak to a human. Was eventually put through to a technical expert who said the Nokia 1616 is not compatible with the new SIM card and has ordered a new phone to be delivered by Tuesday, at zero cost. Well done that man - less than 5 minutes to come to a decision after a week of trying to communicate with the text message based help system.
I am also having trouble with the new SIM. My 91 year old grandmother has an old Nokia phone and when the new SIM is inserted it comes up with an error message saying SIM not valid. Please can you advise ASAP as I do not want her to be without a phone. I am finding it impossible to get through to speak to anyone.