I think this error is occurring because some of your 'Tax Amount' values are empty and do not contain any values? For example:
{
"Client Name": "Alex Wilber",
"Email": "Alex@home.net",
"Vendor Name": "Safe Systems Ltd",
"Due Date": "2022-09-22",
"Tax Amount": ""
}
If this is the case, you can extend the expression to test for empty or missing values and return $0.00:
if(empty(item()?['Tax Amount']),'$0.00',formatNumber(float(item()?['Tax Amount']),'C2'))


Ellis
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