API REST method post

Hello,
In a project, I have to send data to a ninox table from the outside.
I'm using that ninox REST API with the post method.

I'm sending the json structure below to create records on the fly:

[
     {
         "fields": {
             "Data": "Test 1"
         }
     },
     {
         "fields": {
             "Data": "Test 2"
         }
     }
]

But the problem is that it creates me many records, but twice the "Test 1".

Do not I compose the json structure correctly?
Thank you for your help.
Robert