modelInfo as invalid when calling the get custom model API in form recognizer

Question

When I try to train a custom model with labels in form recognizer. I am getting modelInfo as invalid with error code 2102 and message as "Only 3 valid input document(s) were found. Please provide at least 5 input documents."

I have checked all the ocr and labels json files in other tools also and they are showing it as valid jsons.

Also checked for the custom training documents that I have uploaded, they are also valid documents.

Here is the error I am getting:

{
"modelInfo": {
"modelId": "11420c20-55d1-4b21-ae04-6d223c6ae0a7",
"status": "invalid",
"createdDateTime": "2020-03-31T06:10:18Z",
"lastUpdatedDateTime": "2020-03-31T06:10:19Z"
},
"trainResult": {
"averageModelAccuracy": 0.0,
"errors": [
{
"code": "2102",
"message": "Only 3 valid input document(s) were found. Please provide at least 5 input documents."
}
]
}
}