A bulk CSV upload to MyPost Business saves retyping every address. But the importer is strict, and when it refuses a file, the message rarely says what to change.

These are the rejections we've dealt with while building Tradewind CSV Exporter for Australia Post, a free WooCommerce plugin that writes MyPost Business files. Each section covers what the error means, how to fix the file by hand, and how the plugin prevents it. If you pasted an error into Google to get here, use Ctrl+F (Cmd+F on a Mac) to jump to it.

On this page:

"The input shipment request is invalid for item content weight"

What it means. This one appears on international shipments. The customs content lines declare more weight than the parcel itself. Each content line's weight is multiplied by its quantity, and the total can't be more than the Item Weight.

It usually comes from small, light items. Australia Post takes weights in kilograms to 3 decimal places and never zero, so anything lighter than a gram has to be declared as 0.001 kg. Forty pieces at 0.3 g each weigh 12 g, but declare 40 g across their content lines. If the parcel is declared at its real weight, the contents outweigh it and the shipment is refused.

Fix it by hand. For each refused row, add up weight times quantity across the content lines, and raise Item Weight to at least that total.

How the plugin prevents it. It works out the contents total for every international order and exports whichever is larger: the parcel weight or the contents.

"Parcel Contents - Value is in error"

The full message reads: "Parcel Contents - Value is in error. The Unit value must be at least 1".

What it means. A customs content line has a value under 1. The usual causes are a free gift, a line discounted to nothing by a 100% coupon, or an item worth less than a dollar each after discounts.

Fix it by hand. Find the content line with a value of 0 or less than 1, and set it to at least 1.

How the plugin prevents it. Content values are exported per unit, after discounts, in whole currency units and never below 1.

"Item Height is in error"

What it means. A dimension breaks Australia Post's format: more than 4 digits before the decimal point, or more than 1 after it. The rule covers length and width as well as height. It's easy to trip when dimensions are calculated rather than typed: a converted or averaged size such as 9.18 or 13.65 cm is refused.

Fix it by hand. Round every Item Length, Item Width and Item Height to one decimal place, or to whole centimetres.

How the plugin prevents it. Dimensions are exported as whole centimetres, converted from your store's own units, so a store measuring in millimetres still exports centimetres. Height is worked out from what's in the parcel, not by stacking every item.

Column names that look right but don't match

What it means. MyPost matches the header row against its required column names character for character. Many CSV writers, including PHP's built-in one, put quotes around any value that contains a space. So the header arrives as "Send From Name" with the quotes, it doesn't match Send From Name, and the file is refused over columns that look fine in a spreadsheet. The message doesn't mention quotes, which is what makes this one hard to spot.

Fix it by hand. Open the file in a plain-text editor, such as Notepad or TextEdit in plain text mode, not a spreadsheet. If the first line has quotes around the column names, remove them and save it as .csv. Check the names are spelled exactly as in Australia Post's template while you're there.

How the plugin prevents it. It quotes a value only when it has to: when the value contains a comma, a quote mark or a line break. The header row goes out unquoted.

A phone number with an apostrophe in front

What it means. A value that starts with +, -, = or @ can run as a formula when the file is opened in Excel, LibreOffice or Google Sheets. Some exporters guard against that by putting an apostrophe in front of any such value. International phone numbers start with +, so +1 555 0100 goes out as '+1 555 0100, and Australia Post rejects the number with the stray apostrophe.

Fix it by hand. Open the file in a plain-text editor, where you see exactly what MyPost sees, and remove the apostrophe from the phone columns.

How the plugin prevents it. It still protects names, addresses and product titles from running as formulas, but leaves a value made only of digits and phone punctuation exactly as it is.

Weights with too many decimals, or no weight at all

What it means. Item Weight is in kilograms, with at most 3 decimal places, and it can't be zero. A product with no weight set in WooCommerce exports as 0, and a store that weighs in grams can end up with grams in a kilogram column.

Fix it by hand. Round weights to 3 decimal places, convert grams to kilograms, and give any zero-weight parcel its real weight.

How the plugin prevents it. Weights are converted from your store's units, rounded to 3 decimal places and never exported as zero. A minimum package weight in the settings covers packaging and products with no weight set.

Names longer than 40 characters

What it means. Australia Post limits recipient and business names to 40 characters. A long company name, or a name with extra details added to it, goes over.

Fix it by hand. Shorten the name to 40 characters or fewer.

How the plugin prevents it. Recipient and business names are trimmed to 40 characters. That includes the order number tag it adds, such as [#1234], so you can match each label to its order.

No return address, or no delivery address

What it means. A manifest with no Send From address is rejected on upload. The Deliver To side goes blank when an order has no shipping address, which happens in stores that don't ask for one, and an exporter copies the empty shipping fields.

Fix it by hand. Fill in the Send From columns on every row. For a blank recipient, copy the billing address from the order.

How the plugin prevents it. It won't export until your Send From name, address line 1, suburb, state and postcode are set, and links you to the settings instead. An order with no shipping address uses its whole billing address, never a mix of the two.

MyPost asks about Schedule 8 on every order

What it means. This isn't an error, but it's the one that eats the most time. Australia Post requires every domestic parcel to say whether it contains Schedule 8 medicines or medicinal cannabis. If the column is missing from your file, the upload still succeeds, but MyPost asks the question again as soon as you open an imported order to edit it, one order at a time.

Fix it by hand. Add a column headed Schedule 8 or medicinal cannabis to your domestic file, with NO on every row. Australia Post rejects any bulk import that declares Yes, so parcels that really do contain Schedule 8 medication need a StarTrack account instead.

How the plugin prevents it. The domestic file includes the column, filled from a setting that defaults to No. International files leave it out, because MyPost never asks for it on an international order.

Not upload errors, but they still come back

Two problems get through the upload and cause trouble later.

  • US parcels with a short HS code. Since 24 July 2026, Australia Post says 6 or 8-digit HS codes on US-bound parcels will no longer be accepted, and items without a 10-digit code may be returned. The free plugin warns after an export that includes US orders if your HS code is shorter than 10 digits. See how to add 10-digit HS codes to WooCommerce products.
  • Vague descriptions to the EU. The EU's ICS2 customs system rejects descriptions such as "goods", "merchandise", "gifts", "items", "various" or "misc". Describe what's in the parcel: "sterling silver earrings", not "jewellery items". The plugin ships with the description blank and holds international exports until you set one.

Before you upload

  • Header row with no quotes around the names
  • Dimensions to one decimal place at most
  • Weights in kilograms, 3 decimal places at most, never zero
  • International parcels weigh at least as much as their contents
  • Every content value at least 1
  • Names 40 characters or fewer
  • Send From and Deliver To filled on every row
  • Schedule 8 column on domestic files, set to NO
  • 10-digit HS codes on US parcels, specific descriptions on EU ones

For the options for getting orders out of WooCommerce in the first place, see how to get WooCommerce orders into Australia Post without retyping them.

A file MyPost Business accepts the first time.
Download Tradewind CSV Exporter for Australia Post, free on WordPress.org. Every fix above is built in.

Not affiliated with Australia Post. "Australia Post", "MyPost Business" and "StarTrack" are trademarks of the Australian Postal Corporation.