Same order number as an existing order
DHL Express Commerce will not import a record that has the same order number as an existing imported order. You can delete orders via the DHL Express Commerce GUI to get around this.
Missing mandatory fields
If a mandatory field is not populated, the record will be ignored. Mandatory fields are: Order Number, Name, Street, Suburb, Postcode, Date and Country.
Commas in fields
If you have commas in your data, this will cause errors when DHL Express Commerce parses the file.
Wrong CSV format
Some localisations (particularly European) of Excel format CSV files with semicolons instead of commas as delimiters. DHL Express Commerce will not read these files. You can check this easily by opening the file in Notepad and seeing if the file contains semicolons.
Rules
If some orders are not being imported, check that you're not using any rules that might be affecting the orders you are importing. Simply go to Settings -> Rules. In particular, check for rules that have Import Order as an action.