Getting unexpected validation error "Account must be valid/Tax rate must be valid"

[cb-charchit]

I am trying to make this request through Xero API Explorer

https://api-explorer.xero.com/accounting/invoices/createinvoices?query-unitdp=4

{
  "Invoices": [
    {
      "Type": "ACCREC",
      "Contact": {
        "ContactID": "15976e62-37ad-4065-8bba-d8c5c264e078"
      },
      "LineItems": [
        {
          "Description": "tiered-plan",
          "Quantity": 8555500,
          "UnitAmount": 0.000149611361,
          "AccountCode": "4000",
          "TaxType": "TAX001",
          "taxAmount": 256,
          "ItemCode": "cp_oct17_tiered",
          "LineAmount": 1280
        },
        {
          "Description": "stair-step",
          "Quantity": 8555500,
          "UnitAmount": 0.000029104,
          "AccountCode": "4000",
          "TaxType": "TAX001",
          "taxAmount": 49.8,
          "ItemCode": "cp_oct17_stairstep",
          "LineAmount": 249
        }
      ],
      "Date": "2023-03-11",
      "DueDate": "2022-12-10",
      "Reference": "Website Design",
      "Status": "AUTHORISED"
    }
  ]
}

Getting below validation error:

"ValidationErrors": [
        {
          "Message": "Account must be valid."
        },
        {
          "Message": "Tax rate must be valid."
        }
      ]

This is totally unexpected, as I am using same account and same tax code for other requests as well and all of them getting success.

Later I tried altering content of above request, I updated UnitAmount for second lineItem from
"UnitAmount": 0.000029104 to "UnitAmount": 0.0000291

And to my surprise, old validation error gone and now I am getting mismatch error.

New Request

{
  "Invoices": [
    {
      "Type": "ACCREC",
      "Contact": {
        "ContactID": "15976e62-37ad-4065-8bba-d8c5c264e078"
      },
      "LineItems": [
        {
          "Description": "tiered-plan",
          "Quantity": 8555500,
          "UnitAmount": 0.000149611361,
          "AccountCode": "4000",
          "TaxType": "TAX001",
          "taxAmount": 256,
          "ItemCode": "cp_oct17_tiered",
          "LineAmount": 1280
        },
        {
          "Description": "stair-step",
          "Quantity": 8555500,
          "UnitAmount": 0.0000291,
          "AccountCode": "4000",
          "TaxType": "TAX001",
          "taxAmount": 49.8,
          "ItemCode": "cp_oct17_stairstep",
          "LineAmount": 249
        }
      ],
      "Date": "2023-03-11",
      "DueDate": "2022-12-10",
      "Reference": "Website Design",
      "Status": "AUTHORISED"
    }
  ]
}

Response Error

"ValidationErrors": [
        {
          "Message": "The line total 249.00 does not match the expected line total 248.97"
        }
      ]

I would like to know what does Account must be valid / Tax rate must be valid error mean and what was the reason for this error as I am using same account and tax rate for all other requests. Was there some other internal error which is not passed in final response ?

[github-actions]

PETOSS-359

[github-actions]

Thanks for raising an issue, a ticket has been created to track your request