diff --git a/common/src/main/java/org/keycloak/common/util/KeycloakUriBuilder.java b/common/src/main/java/org/keycloak/common/util/KeycloakUriBuilder.java
index 5b27f98879..b9e56ea018 100755
--- a/common/src/main/java/org/keycloak/common/util/KeycloakUriBuilder.java
+++ b/common/src/main/java/org/keycloak/common/util/KeycloakUriBuilder.java
@@ -458,13 +458,15 @@ public class KeycloakUriBuilder {
             buffer.append(ssp);
         } else if (userInfo != null || host != null || port != -1) {
             buffer.append("//");
-            if (userInfo != null)
+            if (userInfo != null) {
+                if (host == null || host.isEmpty()) throw new RuntimeException("empty host name, but userInfo supplied");
                 replaceUserInfoParameter(paramMap, fromEncodedMap, isTemplate, userInfo, buffer).append("@");
+            }
             if (host != null) {
-                if ("".equals(host)) throw new RuntimeException("empty host name");
                 replaceParameter(paramMap, fromEncodedMap, isTemplate, host, buffer, encodeSlash);
             }
             if (port != -1 && (preserveDefaultPort || !(("http".equals(scheme) && port == 80) || ("https".equals(scheme) && port == 443)))) {
+                if (host == null || host.isEmpty()) throw new RuntimeException("empty host name, but port supplied");
                 buffer.append(":").append(Integer.toString(port));
             }
         } else if (authority != null) {
diff --git a/common/src/test/java/org/keycloak/common/util/KeycloakUriBuilderTest.java b/common/src/test/java/org/keycloak/common/util/KeycloakUriBuilderTest.java
index 950b3db7c0..e902fa7df7 100644
--- a/common/src/test/java/org/keycloak/common/util/KeycloakUriBuilderTest.java
+++ b/common/src/test/java/org/keycloak/common/util/KeycloakUriBuilderTest.java
@@ -92,4 +92,10 @@ public class KeycloakUriBuilderTest {
         Assert.assertEquals("https://user-info%E2%82%AC@localhost:8443", KeycloakUriBuilder.fromUri(
                 "https://user-info€@localhost:8443", false).buildAsString());
     }
+
+    @Test
+    public void testEmptyHostname() {
+        Assert.assertEquals("app.immich:///oauth-callback", KeycloakUriBuilder.fromUri(
+                "app.immich:///oauth-callback").buildAsString());
+    }
 }