diff --git a/src/Control/Email/Email.php b/src/Control/Email/Email.php
index 7396a129c..b7184c35e 100644
--- a/src/Control/Email/Email.php
+++ b/src/Control/Email/Email.php
@@ -289,8 +289,19 @@ class Email extends ViewableData
      */
     private function getDefaultFrom(): string
     {
-        $defaultFrom = $this->config()->get('admin_email');
-        if (!$defaultFrom) {
+        // admin_email can have a string or an array config
+        // https://docs.silverstripe.org/en/4/developer_guides/email/#administrator-emails
+        $adminEmail = $this->config()->get('admin_email');
+        if (is_array($adminEmail) && count($adminEmail) > 0) {
+            $defaultFrom = array_keys($adminEmail)[0];
+        } else {
+            if (is_string($adminEmail)) {
+                $defaultFrom = $adminEmail;
+            } else {
+                $defaultFrom = '';
+            }
+        }
+        if (empty($defaultFrom)) {
             $host = Director::host();
             if (empty($host)) {
                 throw new RuntimeException('Host not defined');
diff --git a/tests/php/Control/Email/EmailTest.php b/tests/php/Control/Email/EmailTest.php
index 6c88490ec..4781f9975 100644
--- a/tests/php/Control/Email/EmailTest.php
+++ b/tests/php/Control/Email/EmailTest.php
@@ -677,11 +677,22 @@ class EmailTest extends SapphireTest
         $method->setAccessible(true);
 
         // default to no-reply@mydomain.com if admin_email config not set
+        Email::config()->set('admin_email', null);
         $this->assertSame('no-reply@www.mysite.com', $method->invokeArgs($email, []));
 
-        // use admin_email config
+        // default to no-reply@mydomain.com if admin_email config is misconfigured
+        Email::config()->set('admin_email', 123);
+        $this->assertSame('no-reply@www.mysite.com', $method->invokeArgs($email, []));
+
+        // use admin_email config string syntax
         Email::config()->set('admin_email', 'myadmin@somewhere.com');
         $this->assertSame('myadmin@somewhere.com', $method->invokeArgs($email, []));
+        $this->assertTrue(true);
+
+        // use admin_email config array syntax
+        Email::config()->set('admin_email', ['anotheradmin@somewhere.com' => 'Admin-email']);
+        $this->assertSame('anotheradmin@somewhere.com', $method->invokeArgs($email, []));
+        $this->assertTrue(true);
     }
 
     /**