diff --git a/src/main/java/hudson/tasks/MailSender.java b/src/main/java/hudson/tasks/MailSender.java
index f4afa87d..4ff05646 100644
--- a/src/main/java/hudson/tasks/MailSender.java
+++ b/src/main/java/hudson/tasks/MailSender.java
@@ -369,7 +369,7 @@ private MimeMessage createEmptyMail(final Run<?, ?> run, final TaskListener list
                 // people who made a change in the upstream
                 String projectName = address.substring("upstream-individuals:".length());
                 // TODO 1.590+ Jenkins.getActiveInstance
-                final Jenkins jenkins = Jenkins.getInstance();
+                final Jenkins jenkins = Jenkins.getInstanceOrNull();
                 if (jenkins == null) {
                     listener.getLogger().println("Jenkins is not ready. Cannot retrieve project "+projectName);
                     continue;
diff --git a/src/main/java/jenkins/plugins/mailer/tasks/MimeMessageBuilder.java b/src/main/java/jenkins/plugins/mailer/tasks/MimeMessageBuilder.java
index bf64639e..d5bc4cd2 100644
--- a/src/main/java/jenkins/plugins/mailer/tasks/MimeMessageBuilder.java
+++ b/src/main/java/jenkins/plugins/mailer/tasks/MimeMessageBuilder.java
@@ -216,7 +216,7 @@ public MimeMessage buildMimeMessage() throws MessagingException, UnsupportedEnco
     }
 
     private void setJenkinsInstanceIdent(MimeMessage msg) throws MessagingException {
-        if (Jenkins.getInstance() != null) {
+        if (Jenkins.getInstanceOrNull() != null) {
             String encodedIdentity;
             try {
                 RSAPublicKey publicKey = InstanceIdentity.get().getPublic();