diff -Naru a/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/servlet/SsoPostLoginServlet.java b/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/servlet/SsoPostLoginServlet.java
--- a/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/servlet/SsoPostLoginServlet.java	2020-11-19 01:15:47.000000000 +0800
+++ b/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/servlet/SsoPostLoginServlet.java	2022-06-06 10:28:53.426920000 +0800
@@ -8,6 +8,7 @@
 
 import javax.naming.InitialContext;
 import javax.naming.NamingException;
+import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -41,7 +42,7 @@
     }
 
     @Override
-    public void init() {
+    public void init() throws ServletException {
         String strVal = getServletConfig().getInitParameter("login-as-admin");
         if (strVal == null) {
             throw new RuntimeException("No login-as-admin init parameter specified for SsoPostLoginServlet.");
diff -Naru a/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/SsoUtils.java b/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/SsoUtils.java
--- a/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/SsoUtils.java	2020-11-19 01:15:47.000000000 +0800
+++ b/backend/manager/modules/aaa/src/main/java/org/ovirt/engine/core/aaa/SsoUtils.java	2022-06-06 10:27:53.774598000 +0800
@@ -135,7 +135,6 @@
         if (StringUtils.isNotBlank(alternateFqdnString)) {
             Arrays.stream(alternateFqdnString.trim().split("\\s *"))
                     .filter(StringUtils::isNotBlank)
-                    .map(String::toLowerCase)
                     .forEach(allowedDomains::add);
         }
 
@@ -144,7 +143,7 @@
 
     private static String parseHostFromUrl(String url, String urlPropertyName) {
         try {
-            return new URI(url).getHost().toLowerCase();
+            return new URI(url).getHost();
         } catch (URISyntaxException e) {
             throw new IllegalStateException(urlPropertyName + " not a valid URI: " + url);
         }
diff -Naru a/backend/manager/modules/aaa/src/test/java/org/ovirt/engine/core/aaa/SsoUtilsTest.java b/backend/manager/modules/aaa/src/test/java/org/ovirt/engine/core/aaa/SsoUtilsTest.java
--- a/backend/manager/modules/aaa/src/test/java/org/ovirt/engine/core/aaa/SsoUtilsTest.java	2020-11-19 01:15:47.000000000 +0800
+++ b/backend/manager/modules/aaa/src/test/java/org/ovirt/engine/core/aaa/SsoUtilsTest.java	2022-06-06 10:26:52.261144000 +0800
@@ -38,23 +38,6 @@
     }
 
     @Test
-    public void shouldMatchAppUrlDomainOnAlternateSSOEngineUrlRegardlessUpperCase() {
-        // given
-        EngineLocalConfig.getInstance(new HashMap<>() {
-            {
-                put("SSO_ENGINE_URL", "https://engine.example.com:8221/ovirt-engine");
-                put("SSO_ALTERNATE_ENGINE_FQDNS", "engine1.example.com ALTERNATE-engine.example.com");
-            }
-        });
-
-        // when
-        boolean valid = SsoUtils.isDomainValid("https://alternate-engine.EXAMPLE.com:20001/somerest/api_v9");
-
-        // then
-        Assertions.assertTrue(valid);
-    }
-
-    @Test
     public void shouldAllowBlankAppUrl() {
         // given
         EngineLocalConfig.getInstance(new HashMap<>() {
@@ -103,23 +86,6 @@
 
         // then
         Assertions.assertTrue(valid);
-    }
-
-    @Test
-    public void shouldMatchAppUrlDomainOnSSOEngineUrlRegardlessUpperCase() {
-        // given
-        EngineLocalConfig.getInstance(new HashMap<>() {
-            {
-                put("SSO_ENGINE_URL", "https://engine.EXAMPLE.com:30003/ovirt-engine");
-                put("SSO_ALTERNATE_ENGINE_FQDNS", "alternate-engine.example.com");
-            }
-        });
-
-        // when
-        boolean valid = SsoUtils.isDomainValid("https://ENGINE.example.com:20001/somerest/api_v9");
-
-        // then
-        Assertions.assertTrue(valid);
     }
 
     @Test
