diff --git a/.gitignore b/.gitignore
index 63188ef5..91d18d0a 100644
Binary files a/.gitignore and b/.gitignore differ
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 00000000..7b016a89
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "java.compile.nullAnalysis.mode": "automatic"
+}
\ No newline at end of file
diff --git a/src/main/java/hudson/plugins/emailext/ExtendedEmailPublisher.java b/src/main/java/hudson/plugins/emailext/ExtendedEmailPublisher.java
index 193971f7..4ac1cd1d 100644
--- a/src/main/java/hudson/plugins/emailext/ExtendedEmailPublisher.java
+++ b/src/main/java/hudson/plugins/emailext/ExtendedEmailPublisher.java
@@ -856,16 +856,17 @@ private ClassLoader expandClasspath(ExtendedEmailPublisherContext context, Class
         }
 
         boolean useSecurity = Jenkins.get().isUseSecurity();
-        if (!classpathList.isEmpty()) {
-            GroovyClassLoader gloader = new GroovyClassLoader(loader);
-            gloader.setShouldRecompile(true);
-            for (ClasspathEntry entry : classpathList) {
-                if (useSecurity) {
-                    ScriptApproval.get().using(entry);
+       if (!classpathList.isEmpty()) {
+            try (GroovyClassLoader gloader = new GroovyClassLoader(loader)) {
+                gloader.setShouldRecompile(true);
+                for (ClasspathEntry entry : classpathList) {
+                    if (useSecurity) {
+                        ScriptApproval.get().using(entry);
+                    }
+                    gloader.addURL(entry.getURL());
                 }
-                gloader.addURL(entry.getURL());
+                loader = gloader;
             }
-            loader = gloader;
         }
         if (useSecurity) {
             return GroovySandbox.createSecureClassLoader(loader);
diff --git a/src/main/java/hudson/plugins/emailext/MailAccount.java b/src/main/java/hudson/plugins/emailext/MailAccount.java
index bfb4e4e1..ff6a4a87 100644
--- a/src/main/java/hudson/plugins/emailext/MailAccount.java
+++ b/src/main/java/hudson/plugins/emailext/MailAccount.java
@@ -170,7 +170,7 @@ public FormValidation doCheckCredentialsId(
             if (CredentialsProvider.listCredentials(
                             StandardUsernamePasswordCredentials.class,
                             item,
-                            item instanceof Queue.Task t ? Tasks.getAuthenticationOf(t) : ACL.SYSTEM,
+                            item instanceof Queue.Task t ? Tasks.getAuthenticationOf2(t) : ACL.SYSTEM2,
                             null,
                             CredentialsMatchers.withId(value))
                     .isEmpty()) {
@@ -310,7 +310,7 @@ private void migrateCredentials() {
         }
         final List<StandardUsernamePasswordCredentials> credentials = CredentialsMatchers.filter(
                 CredentialsProvider.lookupCredentials(
-                        StandardUsernamePasswordCredentials.class, Jenkins.get(), ACL.SYSTEM, domainRequirement),
+                        StandardUsernamePasswordCredentials.class, Jenkins.get(), ACL.SYSTEM2, domainRequirement),
                 CredentialsMatchers.withUsername(smtpUsername));
         for (final StandardUsernamePasswordCredentials cred : credentials) {
             if (smtpPassword.getPlainText().equals(Secret.toString(cred.getPassword()))) {