diff --git a/src/main/java/com/ffii/tsms/modules/common/mail/service/MailReminderService.kt b/src/main/java/com/ffii/tsms/modules/common/mail/service/MailReminderService.kt
index 0a27fe2..5b1bcf2 100644
--- a/src/main/java/com/ffii/tsms/modules/common/mail/service/MailReminderService.kt
+++ b/src/main/java/com/ffii/tsms/modules/common/mail/service/MailReminderService.kt
@@ -148,7 +148,7 @@ open class MailReminderService(
                         key.second, // recordDate
                         key.first, // staffId
                         records.sumOf { it.hours },
-                        key.third
+                        key.third // joinDate
                     )
                 }
             val goodStaffsList = filteredLastMonthDays.map { date ->
@@ -237,7 +237,7 @@ open class MailReminderService(
                         key.second, // recordDate
                         key.first, // staffId
                         records.sumOf { it.hours },
-                        key.third
+                        key.third // joinDate
                     )
                 }
 
diff --git a/src/main/java/com/ffii/tsms/modules/common/mail/web/models/WorkHourRecords.kt b/src/main/java/com/ffii/tsms/modules/common/mail/web/models/WorkHourRecords.kt
index 942ba17..10691ac 100644
--- a/src/main/java/com/ffii/tsms/modules/common/mail/web/models/WorkHourRecords.kt
+++ b/src/main/java/com/ffii/tsms/modules/common/mail/web/models/WorkHourRecords.kt
@@ -12,7 +12,7 @@ data class WorkHourRecordsWithJoinDate(
     val staffId: Long,
     val recordDate: LocalDate,
     val hours: Double,
-    val joinDate: LocalDate
+    val joinDate: LocalDate? = LocalDate.of(1970,1,1)
 )
 
 data class StaffRecords(