Azure Data Factory 'Failed Validation' with Folder does not exist I uploaded whole set of .txt files in my blob storage with folder structure Year/Month/day.

I circled the folder structure. 


Then in the pipeline I have following dataset created.

 "type": "AzureBlob",
        "linkedServiceName": "blob-store",
        "typeProperties": {
            "fileName": "{Day}.csv",
            "folderPath": "adf-data/sales/{Year}/{Month}",
            "format": {
                "type": "TextFormat",
                "columnDelimiter": "\t",
                "firstRowAsHeader": true
            },
            "partitionedBy": [
                {
                    "name": "Year",
                    "value": {
                        "type": "DateTime",
                        "date": "SliceStart",
                        "format": "yyyy"
                    }
                },
                {
                    "name": "Month",
                    "value": {
                        "type": "DateTime",
                        "date": "SliceStart",
                        "format": "MM"
                    }
                },
                {
                    "name": "Day",
                    "value": {
                        "type": "DateTime",
                        "date": "SliceStart",
                        "format": "dd"
                    }
                }
            ]
        },
        "availability": {
            "frequency": "Day",
            "interval": 1
        },
        "external": true,
        "policy": {}
    }


When I run the pipeline I am getting an error with folder does not exist.

Question:
What can I do to troubleshoot this further or fix?
I had wrong file extension.  Error message was misleading. Instead of cannot find file I thought the error was about missing folder.

I had to change this

 "typeProperties": {
            "fileName": "{Day}.csv",
            "folderPath": "adf-data/sales/{Year}/{Month}",
            "format": {
                "type": "TextFormat",
                "columnDelimiter": "\t",
                "firstRowAsHeader": true
            },


To (change file extension from csv to txt)

"typeProperties": {
            "fileName": "{Day}.txt",
            "folderPath": "adf-data/sales/{Year}/{Month}",
            "format": {
                "type": "TextFormat",
                "columnDelimiter": "\t",
                "firstRowAsHeader": true
            },