The problem lies in the same misunderstanding of the previous question. In the specification of the inspections you have:

 "inspections" : { 
            "type" : "array",
            "items" : {
                "type" : "object",
                "maxProperties": 1,
                "minProperties": 1,
                "additionalProperties" : {
                    "$ref" : "#/definitions/inspection"
                }
            }
        }

This means that inspections must be an array, and its items must be objects with a single property. That property must comply with #/definitions/inspection schema.

According to your current schema, inspections items should be like:

"inspections" : [{
        "anyKeyIsValidHere" : {
            "expected" : "MVA",
            "found" : 0.0,
            "inspection" : "Fascia",
            "location" : "rear_left",
            "state" : 0
        }
    }
]

Hence, in this case, reversely than in your previous question, your inspections item should simply be like this:

"inspections" : {
    "type" : "array",
    "items" : {
        "$ref" : "#/definitions/inspection"
    }
}

A final advice. Try to build the schemas step by step, ensuring that each desired constraint is properly enforced. That also helps to make more focused SO questions.

This works:

{
  "id": "#",
  "$schema": "http://json-schema.org/draft-04/schema#",
  "description": "parameters schema",
  "definitions": {
    "item": {
      "type": "object",
      "properties": {
        "comment": {
          "type": "string"
        },
        "max_channels": {
          "type": "integer",
          "minimum": 0,
          "maximum": 10000,
          "additionalProperties": false
        }
      },
      "additionalProperties": false,
      "required": [
        "max_channels"
      ]
    }
  },
  "type": "object",
  "properties": {
    "feeder_tx": {
      "type": "array",
      "minItems": 1,
      "maxItems": 4,
      "items": {
        "$ref": "#/definitions/item"
      }
    }
  },
  "required": [
    "feeder_tx"
  ]
}

Tried using:

• http://www.jsonschemavalidator.net/
• https://jsonschemalint.com/#/version/draft-04/markup/json
• https://json-schema-validator.herokuapp.com/

You have defined your schema correctly, except that it doesn't match the data you say you are validating. If you change the property names to match the schema, you still have one issue. If you want to allow "toll" and "message" to be null, you can do the following.

{
  "type": "array",
  "items": {
    "type": "object",
    "properties": {
      "loc": {
        "type": "string"
      },
      "toll": {
        "type": ["string", "null"]
      },
      "message": {
        "type": ["string", "null"]
      }
    },
    "required": [
      "loc"
    ]
  }
}

However, that isn't related to the error message you are getting. That message means that data you are validating is not an array. The example data you posted should not result in this error. Are you running the validator on some data other than what is posted in the question?

"type": "array",
"items": { // this schema applies to all items
  "type": "object",
  "required": [ "address", "first_name", "last_name" ],
  "properties": {
    "address": { "type": "string", ... },
    .. all your other property definitions here...
  },
  "oneOf": [
    { "required": [ "phone_ number" ] },
    { "required": [ "cell_ number" ] }
  ]
}

See https://json-schema.org/understanding-json-schema/reference/combining.html and https://json-schema.org/understanding-json-schema/reference/array.html