Fixed issue #2397 - Unable to process emails without From (but with Sender) header.

app/models/channel/email_parser.rb

@@ -5,7 +5,7 @@
 class Channel::EmailParser
   EMAIL_REGEX = /.+@.+/
   RECIPIENT_FIELDS = %w[to cc delivered-to x-original-to envelope-to].freeze
-  SENDER_FIELDS = %w[from reply-to return-path].freeze
+  SENDER_FIELDS = %w[from reply-to return-path sender].freeze
 
 =begin
 

test/unit/email_process_test.rb

@@ -107,6 +107,45 @@ Some Textäöü",
           ],
         },
       },
+      {
+        data: "Sender: me_sender@example.com
+To: customer@example.com
+Subject: äöü some subject 3
+
+Some Textäöü",
+        channel: {
+          trusted: false,
+        },
+        success: true,
+        result: {
+          0 => {
+            priority: '2 normal',
+            title: 'äöü some subject 3',
+          },
+          1 => {
+            body: 'Some Textäöü',
+            sender: 'Customer',
+            type: 'email',
+            internal: false,
+          },
+        },
+        verify: {
+          users: [
+            {
+              firstname: '',
+              lastname: '',
+              fullname: 'me@example.com',
+              email: 'me@example.com',
+            },
+            {
+              firstname: '',
+              lastname: '',
+              fullname: 'customer@example.com',
+              email: 'customer@example.com',
+            },
+          ],
+        },
+      },
       {
         data: "From: me@example.com
 To: customer@example.com