diff --git a/src/mailer.js b/src/mailer.js
index f5b43a5a6..f505b28d8 100644
--- a/src/mailer.js
+++ b/src/mailer.js
@@ -228,22 +228,23 @@ function backupFailed(mailTo, errorMessage, logUrl) {
     });
 }
 
-function certificateRenewalError(mailTo, domain, message) {
+function certificateRenewalError(mailTo, domain, message, callback) {
     assert.strictEqual(typeof mailTo, 'string');
     assert.strictEqual(typeof domain, 'string');
     assert.strictEqual(typeof message, 'string');
+    assert.strictEqual(typeof callback, 'function');
 
     getMailConfig(function (error, mailConfig) {
         if (error) return debug('Error getting mail details:', error);
 
-        var mailOptions = {
+        const mailOptions = {
             from: mailConfig.notificationFrom,
             to: mailTo,
             subject: `[${mailConfig.cloudronName}] Certificate renewal error`,
             text: render('certificate_renewal_error.ejs', { domain: domain, message: message, format: 'text' })
         };
 
-        sendMail(mailOptions);
+        sendMail(mailOptions, callback);
     });
 }
 
diff --git a/src/notifications.js b/src/notifications.js
index ea5ab95ec..8e7b8aac9 100644
--- a/src/notifications.js
+++ b/src/notifications.js
@@ -22,6 +22,7 @@ exports = module.exports = {
 };
 
 const assert = require('assert'),
+    async = require('async'),
     auditSource = require('./auditsource.js'),
     BoxError = require('./boxerror.js'),
     changelog = require('./changelog.js'),
@@ -178,15 +179,21 @@ async function certificateRenewalError(eventId, vhost, errorMessage) {
     assert.strictEqual(typeof vhost, 'string');
     assert.strictEqual(typeof errorMessage, 'string');
 
-    const getAdmins = util.callbackify(users.getAdmins);
+    return new Promise((resolve, reject) => {
+        users.getAdmins(function (error, admins) {
+            if (error) return reject(error);
 
-    const admins = await getAdmins();
+            async.eachSeries(admins, function (admin, iteratorDone) {
+                mailer.certificateRenewalError(admin.email, vhost, errorMessage, iteratorDone);
+            }, async function (error) {
+                if (error) return reject(error);
 
-    for (const admin of admins) {
-        mailer.certificateRenewalError(admin.email, vhost, errorMessage);
-    }
+                await add(eventId, `Certificate renewal of ${vhost} failed`, `Failed to renew certs of ${vhost}: ${errorMessage}. Renewal will be retried in 12 hours.`);
 
-    await add(eventId, `Certificate renewal of ${vhost} failed`, `Failed to renew certs of ${vhost}: ${errorMessage}. Renewal will be retried in 12 hours`);
+                resolve();
+            });
+        });
+    });
 }
 
 async function backupFailed(eventId, taskId, errorMessage) {
@@ -205,7 +212,7 @@ async function backupFailed(eventId, taskId, errorMessage) {
     }
     if (count !== 3) return; // less than 3 failures
 
-    const getSuperAdmins = util.callbackify(users.getSuperAdmins);
+    const getSuperAdmins = util.promisify(users.getSuperAdmins);
 
     const superAdmins = await getSuperAdmins();
 
diff --git a/src/reverseproxy.js b/src/reverseproxy.js
index 32029dd69..99de3c8d8 100644
--- a/src/reverseproxy.js
+++ b/src/reverseproxy.js
@@ -438,7 +438,7 @@ function ensureCertificate(vhost, domain, auditSource, callback) {
             acmeApi.getCertificate(vhost, domain, acmePaths, apiOptions, async function (error) {
                 debug(`ensureCertificate: error: ${error ? error.message : 'null'} cert: ${acmePaths.certFilePath || 'null'}`);
 
-                eventlog.add(currentBundle ? eventlog.ACTION_CERTIFICATE_RENEWAL : eventlog.ACTION_CERTIFICATE_NEW, auditSource, { domain: vhost, errorMessage: error ? error.message : '', notAfter });
+                await safe(eventlog.add(currentBundle ? eventlog.ACTION_CERTIFICATE_RENEWAL : eventlog.ACTION_CERTIFICATE_NEW, auditSource, { domain: vhost, errorMessage: error ? error.message : '', notAfter }));
 
                 if (error && currentBundle && (notAfter - new Date() > 0)) { // still some life left in this certificate
                     debug('ensureCertificate: continue using existing bundle since renewal failed');