When uploading a CSV file with comma-separated values of guests' email addresses into the Punchh platform, it is always best to choose "CSV UTF-8" as the .csv file type, as seen below. This will ensure that you don't run into errors as long as the file is formatted properly with legitimate data points.
For header configuration, please consult this Article.
If further assistance is required, submit a ticket to Punchh Support. (For help submitting a ticket, click here)