diff --git a/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailReader.kt b/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailReader.kt
index f5b5933..66d5d41 100644
--- a/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailReader.kt
+++ b/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailReader.kt
@@ -110,7 +110,7 @@ class MailReader(
 
             if (attachmentsWithEInvoice.isNotEmpty()) {
                 return MailWithInvoice(
-                    message.from.joinToString(), message.subject,
+                    message.from?.joinToString(), message.subject,
                     message.sentDate?.let { map(it) }, map(message.receivedDate), message.messageNumber,
                     getPlainTextBody(parts), getHtmlBody(parts),
                     attachmentsWithEInvoice
diff --git a/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailWithInvoice.kt b/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailWithInvoice.kt
index 3f56b39..2c60112 100644
--- a/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailWithInvoice.kt
+++ b/e-invoicing-domain/src/main/kotlin/net/codinux/invoicing/mail/MailWithInvoice.kt
@@ -4,7 +4,7 @@ import java.time.Instant
 import java.time.ZoneId
 
 class MailWithInvoice(
-    val sender: String,
+    val sender: String?,
     val subject: String,
     val sent: Instant?,
     val received: Instant,