Vonage WhatsApp messages suddenly stopped working - whatsapp

Question

I have recently joined a company that is using Vonage and we have WhatsApp communications which was working fine in both dev and production that have both suddenly stopped working.
The shape of the incoming json looks to have changed significantly, but I have changed the code that is reading this and am able to read the messages into the system.
The problem that I have now, is outgoing message is not being accepted.
If I send this json body over
{
"from": "4474183xxxxx",
"to": "4474719xxxxx",
"message": {
"Type": "text",
"content": "Hello! I’m CAI, A Virtual Chat-bot assistant. blurb, more blurb.... .\n\n1. Okay I understand\n\nChoose any one option. Type \"1\" to choose first option."
}
}
I get the following response
{
"Status": "fail", // custom one to my company
"e3": {
"Error": {
"body": {
"type": "https://developer.vonage.com/api-errors",
"title": "Your request parameters didn't validate.",
"detail": "Found errors validating 1 of your submitted parameters.",
"invalid_parameters": [
{
"name": "to",
"reason": "Malformed JSON body."
}
],
"instance": "cf4bce73-2db5-4102-b7af-xxxxxx"
},
"headers": {
"date": "Wed, 02 Nov 2022 14:02:08 GMT",
"content-type": "application/problem+json",
"content-length": "287",
"connection": "close",
"x-envoy-upstream-service-time": "3",
"x-frame-options": "deny",
"x-xss-protection": "1; mode=block",
"strict-transport-security": "max-age=31536000; includeSubdomains",
"x-content-type-options": "nosniff",
"server": "envoy"
},
"statusCode": 400
},
"StatCode": 400,
"Response": null
},
"a": {
"label": 6,
"trys": [
[
0,
6,
null,
7
]
],
"ops": []
}
}
However, looking at the shape of the message that is on the website (https://dashboard.nexmo.com/messages/sandbox) and send this message
{
"from": "xxxx",
"to": "xxxx",
"message_type": "text",
"text": "Hello! I’m CAI, blurb... .\n\n1. Okay I understand\n\nChoose any one option. Type \"1\" to choose first option.",
"channel" : "whatsapp"
}
I get this response
{
"Status": "fail",
"e3": {},
"a": {
"label": 6,
"trys": [
[
0,
6,
null,
7
]
],
"ops": []
},
"Message": "Cannot read property 'Type' of undefined"
}
I would be grateful if someone could help me shape the message that needs to be sent to vonage to that this can be sent out to the end user \ recipient correct.
Thanks
Simon