diff --git a/src/main/java/de/gessnerfl/fakesmtp/model/Email.java b/src/main/java/de/gessnerfl/fakesmtp/model/Email.java
index a1b2e700..20fa247d 100644
--- a/src/main/java/de/gessnerfl/fakesmtp/model/Email.java
+++ b/src/main/java/de/gessnerfl/fakesmtp/model/Email.java
@@ -40,8 +40,8 @@ public class Email {
     @Basic(optional = false)
     private String rawData;
 
-    @Column(name = "message_id", nullable = false)
-    @Basic(optional = false)
+    @Column(name = "message_id", nullable = true)
+    @Basic(optional = true)
     private String messageId;
 
     @OneToMany(mappedBy = "email", cascade = CascadeType.ALL, orphanRemoval = true)
@@ -148,8 +148,8 @@ public List<InlineImage> getInlineImages() {
         return inlineImages;
     }
 
-    public String getMessageId() {
-        return messageId;
+    public Optional<String> getMessageId() {
+        return Optional.ofNullable(messageId);
     }
 
     public void setMessageId(String messageId) {
diff --git a/src/main/resources/db/migration/V1_1_0__initial_table_structure.sql b/src/main/resources/db/migration/V1_1_0__initial_table_structure.sql
index bda9e538..a071b49b 100644
--- a/src/main/resources/db/migration/V1_1_0__initial_table_structure.sql
+++ b/src/main/resources/db/migration/V1_1_0__initial_table_structure.sql
@@ -5,7 +5,7 @@ CREATE TABLE email (
     subject CLOB NOT NULL,
     received_on TIMESTAMP NOT NULL,
     raw_data CLOB NOT NULL,
-    message_id VARCHAR(255) NOT NULL,
+    message_id VARCHAR(255),
     PRIMARY KEY (id)
 );