diff --git a/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/h2/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql b/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/h2/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql
new file mode 100644
index 0000000000..76497df4f9
--- /dev/null
+++ b/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/h2/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql
@@ -0,0 +1,14 @@
+--
+-- The contents of this file are subject to the license and copyright
+-- detailed in the LICENSE and NOTICE files at the root of the source
+-- tree and available online at
+--
+-- http://www.dspace.org/license/
+--
+
+-----------------------------------------------------------------------------------
+-- ADD CONSTRAINT on notifyservice table: ldn_url as unique
+-----------------------------------------------------------------------------------
+
+ALTER TABLE notifyservice ADD CONSTRAINT ldn_url_unique UNIQUE (ldn_url);
+
diff --git a/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/postgres/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql b/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/postgres/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql
new file mode 100644
index 0000000000..76497df4f9
--- /dev/null
+++ b/dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/postgres/V8.0_2023.12.05__notifyservice_table_unique_ldn_url.sql
@@ -0,0 +1,14 @@
+--
+-- The contents of this file are subject to the license and copyright
+-- detailed in the LICENSE and NOTICE files at the root of the source
+-- tree and available online at
+--
+-- http://www.dspace.org/license/
+--
+
+-----------------------------------------------------------------------------------
+-- ADD CONSTRAINT on notifyservice table: ldn_url as unique
+-----------------------------------------------------------------------------------
+
+ALTER TABLE notifyservice ADD CONSTRAINT ldn_url_unique UNIQUE (ldn_url);
+
diff --git a/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/NotifyServiceRestRepository.java b/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/NotifyServiceRestRepository.java
index 8c9bc579c1..3671b05498 100644
--- a/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/NotifyServiceRestRepository.java
+++ b/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/NotifyServiceRestRepository.java
@@ -106,6 +106,11 @@ public class NotifyServiceRestRepository extends DSpaceRestRepository<NotifyServ
             }
         }
 
+        if (notifyService.findByLdnUrl(context,notifyServiceRest.getLdnUrl()) != null) {
+            throw new UnprocessableEntityException(format("LDN url already in use %s",
+                notifyServiceRest.getLdnUrl()));
+        }
+
         NotifyServiceEntity notifyServiceEntity = notifyService.create(context);
         notifyServiceEntity.setName(notifyServiceRest.getName());
         notifyServiceEntity.setDescription(notifyServiceRest.getDescription());
diff --git a/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/patch/operation/ldn/NotifyServiceLdnUrlReplaceOperation.java b/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/patch/operation/ldn/NotifyServiceLdnUrlReplaceOperation.java
index 820ade3baf..bad2f280e0 100644
--- a/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/patch/operation/ldn/NotifyServiceLdnUrlReplaceOperation.java
+++ b/dspace-server-webapp/src/main/java/org/dspace/app/rest/repository/patch/operation/ldn/NotifyServiceLdnUrlReplaceOperation.java
@@ -7,6 +7,8 @@
  */
 package org.dspace.app.rest.repository.patch.operation.ldn;
 
+import static java.lang.String.format;
+
 import java.sql.SQLException;
 
 import org.dspace.app.ldn.NotifyServiceEntity;
@@ -50,6 +52,11 @@ public class NotifyServiceLdnUrlReplaceOperation extends PatchOperation<NotifySe
             throw new UnprocessableEntityException("The /ldnurl value must be a string");
         }
 
+        if (notifyService.findByLdnUrl(context,(String) ldnUrl) != null) {
+            throw new UnprocessableEntityException(format("LDN url already in use %s",
+                (String) ldnUrl));
+        }
+
         checkModelForExistingValue(notifyServiceEntity);
         notifyServiceEntity.setLdnUrl((String) ldnUrl);
         notifyService.update(context, notifyServiceEntity);
diff --git a/dspace/config/dspace.cfg b/dspace/config/dspace.cfg
index cedafb2aef..086a2c3ab2 100644
--- a/dspace/config/dspace.cfg
+++ b/dspace/config/dspace.cfg
@@ -780,7 +780,6 @@ event.dispatcher.default.class = org.dspace.event.BasicDispatcher
 # Add rdf here, if you are using dspace-rdf to export your repository content as RDF.
 # Add iiif here, if you are using dspace-iiif.
 # Add orcidqueue here, if the integration with ORCID is configured and wish to enable the synchronization queue functionality
-
 event.dispatcher.default.consumers = versioning, discovery, eperson, submissionconfig, qaeventsdelete, ldnmessage
 
 # The noindex dispatcher will not create search or browse indexes (useful for batch item imports)