diff --git a/src/main/java/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyService.java b/src/main/java/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyService.java
index 423ac2f0..e9469318 100644
--- a/src/main/java/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyService.java
+++ b/src/main/java/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyService.java
@@ -23,7 +23,7 @@ public class PresenceConfirmationProxyService {
     private final PresenceConfirmationService presenceConfirmationService;
 
     public void confirmPresence(PresenceConfirmationProxyInput proxyInput) {
-        var user = userService.get(proxyInput.email());
+        var user = userService.getByMail(proxyInput.email());
 
         var startTime = DEFAULT_START_TIME;
         var endTime = startTime.plusMinutes(Math.round(60 * user.getWorkTime()));
diff --git a/src/main/java/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandler.java b/src/main/java/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandler.java
index cd2944fe..7fe40a02 100644
--- a/src/main/java/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandler.java
+++ b/src/main/java/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandler.java
@@ -72,7 +72,7 @@ private void confirmPresence(String userSlackId,
                                  String latestMessageTimestamp) {
         try {
             var userEmail = getUserEmail(userSlackId);
-            var user = userService.get(userEmail);
+            var user = userService.getByMail(userEmail);
             confirmUserTodayPresence(user, eventMessage);
             addReactionToLatestMessage(channel, latestMessageTimestamp, SUCCESS_EMOJI_NAME);
         } catch (NoSuchUserException | SlackBotException ex) {
diff --git a/src/main/java/info/fingo/urlopia/config/mail/receive/MailDecider.java b/src/main/java/info/fingo/urlopia/config/mail/receive/MailDecider.java
index c6adb189..7263e980 100644
--- a/src/main/java/info/fingo/urlopia/config/mail/receive/MailDecider.java
+++ b/src/main/java/info/fingo/urlopia/config/mail/receive/MailDecider.java
@@ -64,7 +64,7 @@ public void resolve(Mail mail) {
     private void parse(Mail mail){
         var senderMail = mail.getSenderAddress();
         try{
-            var sender = userService.get(senderMail);
+            var sender = userService.getByMail(senderMail);
             mailParser.clear();
             mailParser.parseSubject(mail);
 
diff --git a/src/main/java/info/fingo/urlopia/user/User.java b/src/main/java/info/fingo/urlopia/user/User.java
index 75012bae..8eb79d49 100644
--- a/src/main/java/info/fingo/urlopia/user/User.java
+++ b/src/main/java/info/fingo/urlopia/user/User.java
@@ -25,7 +25,7 @@ public class User {
     @Column(nullable = false, unique = true)
     private String adName;
 
-    @Column(nullable = false, unique = true)
+    @Column(nullable = false)
     private String mail;
 
     private String firstName;
diff --git a/src/main/java/info/fingo/urlopia/user/UserRepository.java b/src/main/java/info/fingo/urlopia/user/UserRepository.java
index 7257cdbd..41809598 100644
--- a/src/main/java/info/fingo/urlopia/user/UserRepository.java
+++ b/src/main/java/info/fingo/urlopia/user/UserRepository.java
@@ -9,7 +9,7 @@
 
 public interface UserRepository extends BaseRepository<User>, JpaRepository<User, Long> {
 
-    Optional<User> findFirstByMail(String mail);
+    Optional<User> findFirstByMailAndActiveTrue(String mail);
 
     Optional<User> findFirstByPrincipalName(String principalName);
 
diff --git a/src/main/java/info/fingo/urlopia/user/UserService.java b/src/main/java/info/fingo/urlopia/user/UserService.java
index 2569440a..2c5f3017 100644
--- a/src/main/java/info/fingo/urlopia/user/UserService.java
+++ b/src/main/java/info/fingo/urlopia/user/UserService.java
@@ -61,9 +61,9 @@ public User get(Long userId) {
                 });
     }
 
-    public User get(String userMail) {
+    public User getByMail(String userMail) {
         return userRepository
-                .findFirstByMail(userMail)
+                .findFirstByMailAndActiveTrue(userMail)
                 .orElseThrow(() -> {
                     log.error("There is no user with email: {}", Anonymizer.anonymizeMail(userMail));
                     return NoSuchUserException.invalidEmail();
diff --git a/src/main/resources/scripts/U3_5_0_2__drop_email_unique_constraint.sql b/src/main/resources/scripts/U3_5_0_2__drop_email_unique_constraint.sql
new file mode 100644
index 00000000..f950dcec
--- /dev/null
+++ b/src/main/resources/scripts/U3_5_0_2__drop_email_unique_constraint.sql
@@ -0,0 +1 @@
+CREATE UNIQUE INDEX users_mail_index ON users (mail);
\ No newline at end of file
diff --git a/src/main/resources/scripts/V3_5_0_2__drop_email_unique_constraint.sql b/src/main/resources/scripts/V3_5_0_2__drop_email_unique_constraint.sql
new file mode 100644
index 00000000..b17fe238
--- /dev/null
+++ b/src/main/resources/scripts/V3_5_0_2__drop_email_unique_constraint.sql
@@ -0,0 +1 @@
+ALTER TABLE users DROP CONSTRAINT IF EXISTS users_mail_index;
\ No newline at end of file
diff --git a/src/test/groovy/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyServiceSpec.groovy b/src/test/groovy/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyServiceSpec.groovy
index af9c1bb4..21dea73a 100644
--- a/src/test/groovy/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyServiceSpec.groovy
+++ b/src/test/groovy/info/fingo/urlopia/api/v2/proxy/presence/PresenceConfirmationProxyServiceSpec.groovy
@@ -27,7 +27,7 @@ class PresenceConfirmationProxyServiceSpec extends Specification {
 
         and:
         def presenceConfirmationProxyInput = new PresenceConfirmationProxyInput(sampleProxyToken, sampleEmail, "")
-        userService.get(sampleEmail) >> sampleUser
+        userService.getByMail(sampleEmail) >> sampleUser
 
         when:
         presenceConfirmationProxyService.confirmPresence(presenceConfirmationProxyInput)
@@ -53,7 +53,7 @@ class PresenceConfirmationProxyServiceSpec extends Specification {
 
         and:
         def presenceConfirmationProxyInput = new PresenceConfirmationProxyInput(sampleProxyToken, sampleEmail, testHours)
-        userService.get(sampleEmail) >> sampleUser
+        userService.getByMail(sampleEmail) >> sampleUser
 
         when:
         presenceConfirmationProxyService.confirmPresence(presenceConfirmationProxyInput)
@@ -96,7 +96,7 @@ class PresenceConfirmationProxyServiceSpec extends Specification {
 
         and:
         def presenceConfirmationProxyInput = new PresenceConfirmationProxyInput(sampleProxyToken, sampleEmail, testHours)
-        userService.get(sampleEmail) >> sampleUser
+        userService.getByMail(sampleEmail) >> sampleUser
 
         when:
         presenceConfirmationProxyService.confirmPresence(presenceConfirmationProxyInput)
diff --git a/src/test/groovy/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandlerSpec.groovy b/src/test/groovy/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandlerSpec.groovy
index 824eacf4..558421ed 100644
--- a/src/test/groovy/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandlerSpec.groovy
+++ b/src/test/groovy/info/fingo/urlopia/api/v2/slack/presence/SlackPresenceConfirmationEventHandlerSpec.groovy
@@ -90,7 +90,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMentionEvent.getText() >> "<@FPA12L32>"
         sampleMentionEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleMention(sampleMentionPayload, sampleContext)
@@ -118,7 +118,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMentionEvent.getText() >> testText
         sampleMentionEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleMention(sampleMentionPayload, sampleContext)
@@ -165,7 +165,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMentionEvent.getText() >> testText
         sampleMentionEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleMention(sampleMentionPayload, sampleContext)
@@ -207,7 +207,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMentionEvent.getText() >> "<@FPA12L32>"
         sampleMentionEvent.getUser() >> sampleUserSlackId
-        userService.get(_ as String) >> {throw NoSuchUserException.invalidEmail()}
+        userService.getByMail(_ as String) >> {throw NoSuchUserException.invalidEmail()}
 
         when:
         handler.handleMention(sampleMentionPayload, sampleContext)
@@ -229,7 +229,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMessageEvent.getText() >> "<@FPA12L32>"
         sampleMessageEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleDirectMessage(sampleMessagePayload, sampleContext)
@@ -257,7 +257,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMessageEvent.getText() >> testText
         sampleMessageEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleDirectMessage(sampleMessagePayload, sampleContext)
@@ -304,7 +304,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMessageEvent.getText() >> testText
         sampleMessageEvent.getUser() >> sampleUserSlackId
-        userService.get(sampleUserMail) >> sampleUser
+        userService.getByMail(sampleUserMail) >> sampleUser
 
         when:
         handler.handleDirectMessage(sampleMessagePayload, sampleContext)
@@ -346,7 +346,7 @@ class SlackPresenceConfirmationEventHandlerSpec extends Specification {
         }
         sampleMessageEvent.getText() >> "<@FPA12L32>"
         sampleMessageEvent.getUser() >> sampleUserSlackId
-        userService.get(_ as String) >> {throw NoSuchUserException.invalidEmail()}
+        userService.getByMail(_ as String) >> {throw NoSuchUserException.invalidEmail()}
 
         when:
         handler.handleDirectMessage(sampleMessagePayload, sampleContext)