Please note that these variable substitution tags, including custom variables, are "case-sensitive." Therefore, you need to use them exactly as prescribed to fetch values and function correctly. Use the following variable substitution pattern (with curly braces, not parentheses) like this: {FIRST_NAME} {LAST_NAME} ${custom1}. For more details, refer to the help file: https://www.questionpro.com/help/personalizing-emails.html