Creating customer fails, error says data isn't valid

[Flashnode-developers]

I'm trying to create a customer with POST https://integration.visma.net/API/controller/api/v1/customer, and I'm getting the following error:

Error inserting the customer. Input data not valid. New customer must have a name specified.

My payload is below. What could be wrong here?

{
  "name": {
    "value": "Flashnode"
  },
  "status": {
    "value": "Active"
  },
  "corporateId": {
    "value": "1234567-8"
  },
  "mainAddress": {
    "value": {
      "addressLine1": {
        "value": "Street 123"
      },
      "postalCode": {
        "value": "40100"
      },
      "city": {
        "value": "City"
      },
      "countryId": {
        "value": "FI"
      }
    }
  },
  "mainContact": {
    "value": {
      "name": {
        "value": "Flashnode"
      },
      "attention": {
        "value": "Firstname Lastname"
      },
      "email": {
        "value": "firstname.lastname@flashnode.com"
      },
      "phone1": {
        "value": "0401234567"
      }
    }
  }
}

[Yıldırım]

Hello, do you know if the manual numbering activated for the Customers in that company ? 
Could you possibly try adding 

"number": {
"value": "xxxxx"
},