Why isn't my spreadsheet working?

If your spreadsheet isn't working with SecureMailMerge, check for file format errors, missing columns, or data import issues in Excel or CSV files.

Updated October 2026

You need at least one ‘To’ column.

Make sure you have at least one column called “To” which contains the email addresses of the recipients.

Do not use AutoFilters.

SecureMailMerge does not support AutoFilters and the campaign will use all the rows in the spreadsheet even if you have a filter applied.

All columns must have a title

If a column does not have a title in the first row, it is ignored and its data cannot be used as a merge field.

Empty rows and rows without an address are skipped

Rows with no data, or with an empty “To” cell, are skipped and do not receive an email. Check the number of records shown in the sidebar after uploading to make sure it matches what you expect. If you see an error about an invalid email address, check that row’s “To” cell for typos or extra characters.

Column headers contain illegal characters

If you see an error about illegal characters in column headers, it means one or more of your column names contain character sequences that conflict with the mail merge engine (such as $$, {{, }}, {%, or %}). Rename the affected columns in your spreadsheet and upload again. See Illegal characters in column headers for the full list and how to fix it.