Hello Stack Exchange Community,

I have a question regarding referencing external columns. In my code below, external columns are referenced using square brackets as specified in Microsoft's online documentation.

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "a",
  "txtContent": "@currentField",
  "attributes": {
    "href": {
      "operator": "+",
      "operands": [
        "mailto:",
        "[$Email]",
        "?subject=Task status&body=Follow Up: Agreements.\r\n---\r\n",
        "Dear [$ContactName]",
        "\r\nJust writing to follow up on that agreement that has been sent on [$StartDate]. Let me know if you have any questions."
      ]
    }
  }
}

However, after doing so fields such as $ContactName and $StarDate do not appear to be properly displaying their associated values. Instead, what appears on my email body is the literal code used to reference the columns (e.g Just writing to follow up on that agreement that has been sent on [$StartDate]).

If anyone knows of the proper way to reference values in external columns within the email body using JSON column formatting please do let me know !

Much appreciated !