diff --git a/server/src/main/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtils.java b/server/src/main/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtils.java
index 2fbef926..9bf2cb44 100644
--- a/server/src/main/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtils.java
+++ b/server/src/main/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtils.java
@@ -103,7 +103,7 @@ public static String getCustomApplicationEndpoint(Config config, Application app
                 throw new ApplicationTypeSchemaProcessingException("Custom application schema does not contain completion endpoint");
             }
             return endpointNode.asText();
-        } catch (JsonProcessingException e) {
+        } catch (JsonProcessingException | IllegalArgumentException e) {
             throw new ApplicationTypeSchemaProcessingException("Failed to get custom application endpoint", e);
         }
     }
diff --git a/server/src/test/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtilsTest.java b/server/src/test/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtilsTest.java
index a98ccfe5..7b4c8585 100644
--- a/server/src/test/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtilsTest.java
+++ b/server/src/test/java/com/epam/aidial/core/server/util/ApplicationTypeSchemaUtilsTest.java
@@ -93,7 +93,7 @@ public void getCustomApplicationSchemaOrThrow_returnsSchema_whenSchemaIdExists()
     }
 
     @Test
-    public void getCustomApplicationSchemaOrThrow_throwsException_whenSchemaNotFound() {
+    public void getCustomApplicationSchemaOrThrow_throws_whenSchemaNotFound() {
         URI schemaId = URI.create("schemaId");
         when(application.getCustomAppSchemaId()).thenReturn(schemaId);
         when(config.getCustomApplicationSchema(schemaId)).thenReturn(null);
@@ -189,4 +189,47 @@ public void filterCustomClientPropertiesWhenNoWriteAccess_returnsOriginalApplica
         Assertions.assertEquals(customProperties, result.getCustomProperties());
     }
 
+    @Test
+    public void modifyEndpointForCustomApplication_setsCustomEndpoint_whenSchemaExists() {
+        when(application.getCustomAppSchemaId()).thenReturn(URI.create("schemaId"));
+        when(config.getCustomApplicationSchema(any())).thenReturn(schema);
+
+        Application result = ApplicationTypeSchemaUtils.modifyEndpointForCustomApplication(config, application);
+
+        Assertions.assertNotSame(application, result);
+        Assertions.assertEquals("http://specific_application_service/opeani/v1/completion", result.getEndpoint());
+    }
+
+    @Test
+    public void modifyEndpointForCustomApplication_throws_whenSchemaIsNull() {
+        when(application.getCustomAppSchemaId()).thenReturn(null);
+
+        Assertions.assertThrows(ApplicationTypeSchemaProcessingException.class,
+                () -> ApplicationTypeSchemaUtils.modifyEndpointForCustomApplication(config, application));
+    }
+
+    @Test
+    public void modifyEndpointForCustomApplication_throws_whenEndpointNotFound() {
+        String schemaWithoutEndpoint = "{"
+                + "\"$schema\": \"https://dial.epam.com/application_type_schemas/schema#\","
+                + "\"$id\": \"https://mydial.epam.com/custom_application_schemas/specific_application_type\","
+                + "\"properties\": {"
+                + "  \"clientFile\": {"
+                + "    \"type\": \"string\","
+                + "    \"format\": \"dial-file-encoded\","
+                + "    \"dial:meta\": {"
+                + "      \"dial:propertyKind\": \"client\","
+                + "      \"dial:propertyOrder\": 1"
+                + "    }"
+                + "  }"
+                + "},"
+                + "\"required\": [\"clientFile\"]"
+                + "}";
+        when(application.getCustomAppSchemaId()).thenReturn(URI.create("schemaId"));
+        when(config.getCustomApplicationSchema(any())).thenReturn(schemaWithoutEndpoint);
+
+        Assertions.assertThrows(ApplicationTypeSchemaProcessingException.class, () ->
+                ApplicationTypeSchemaUtils.modifyEndpointForCustomApplication(config, application));
+    }
+
 }