"There was an error processing your list, please contact customer support for further assistance"
Users attempting to upload an .xls or .xlsx file who receive this error message can often resolve the issue by saving their list as a .csv file. Saving an excel file as a .csv file can also resolve issues that cause some lists to get stuck loading.
To save your list as a CSV file, open your mailing list in Excel. Click the “File” tab on the ribbon and then choose “Save As.” Click the arrow next to “Save as Type” and choose “CSV (Comma Delimited)” from the drop-down list. Change the file name to one you prefer. Select the location to save the file, then click the “Save” button.
Your list will be saved as a .csv file and you can attempt to upload the new file.
Click here to view a quick demo that shows you how to save your list as a csv.
If saving your list as a .csv file does not resolve your issue, try removing line breaks from the list. Click here to view an article that tells you how to do that.