'Email' needs to be the first column in your CSV file. If you're still seeing this error message even though it is already the first column, it could be because your device was purchased in the EU, where the default separator for CSV files is a semi-colon rather than a comma.
If you encounter this error, please use the following workaround to ensure your CSV files will register as valid:
On PC
- Open the CSV file in the Notepad app
- Enter Ctrl + H on your keyboard to launch the Find and Replace pop-up
- Enter a semicolon in the first field
- Enter a comma in the second field
- Click Replace all and close the pop-up
- Save your file and reupload the CSV into ContactMonkey
On Mac
- Open the CSV file in the TextEdit app
- Click Edit → Find → Find and replace in the top menu to launch pop-up
- Enter a semicolon in the first field
- Enter a comma in the second field
- Click All, then click Done
- Save your file and reupload the CSV into ContactMonkey