diff --git a/backend/src/main/java/de/szut/casino/security/service/EmailService.java b/backend/src/main/java/de/szut/casino/security/service/EmailService.java
index f276a3c..83d65e0 100644
--- a/backend/src/main/java/de/szut/casino/security/service/EmailService.java
+++ b/backend/src/main/java/de/szut/casino/security/service/EmailService.java
@@ -28,6 +28,7 @@ public class EmailService {
         this.mailConfig = mailConfig;
         this.mailSender.setHost(mailConfig.host);
         this.mailSender.setPort(mailConfig.port);
+        this.mailSender.setProtocol(mailConfig.protocol);
         if (mailConfig.authenticationEnabled) {
             this.mailSender.setUsername(mailConfig.username);
             this.mailSender.setPassword(mailConfig.password);
diff --git a/backend/src/main/java/de/szut/casino/security/service/MailConfig.java b/backend/src/main/java/de/szut/casino/security/service/MailConfig.java
index 56c7250..8a516fd 100644
--- a/backend/src/main/java/de/szut/casino/security/service/MailConfig.java
+++ b/backend/src/main/java/de/szut/casino/security/service/MailConfig.java
@@ -22,4 +22,7 @@ public class MailConfig {
 
     @Value("${app.mail.from-address}")
     public String fromAddress;
+
+    @Value("${app.mail.protocol}")
+    public String protocol;
 }
diff --git a/backend/src/main/resources/application.properties b/backend/src/main/resources/application.properties
index 0fa2407..7b761a7 100644
--- a/backend/src/main/resources/application.properties
+++ b/backend/src/main/resources/application.properties
@@ -14,6 +14,7 @@ app.mail.port=${MAIL_PORT:1025}
 app.mail.username=${MAIL_USER:null}
 app.mail.password=${MAIL_PASS:null}
 app.mail.from-address=${MAIL_FROM:casino@localhost}
+app.mail.protocol=${MAIL_PROTOCOL:smtp}
 
 spring.application.name=casino