diff --git a/src/pretix/base/services/mail.py b/src/pretix/base/services/mail.py
index 7d58d64116..3b1b13f9d0 100644
--- a/src/pretix/base/services/mail.py
+++ b/src/pretix/base/services/mail.py
@@ -32,7 +32,6 @@
 # Unless required by applicable law or agreed to in writing, software distributed under the Apache License 2.0 is
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
-
 import hashlib
 import inspect
 import logging
@@ -43,9 +42,6 @@ import smtplib
 import uuid
 import warnings
 from datetime import timedelta
-from email import encoders, message_from_bytes
-from email.message import Message
-from email.mime.base import MIMEBase
 from email.mime.image import MIMEImage
 from email.utils import formataddr
 from typing import Any, Dict, List, Optional, Sequence, Union
@@ -57,15 +53,12 @@ from celery import chain
 from celery.exceptions import MaxRetriesExceededError
 from django.conf import settings
 from django.core.files.storage import default_storage
-from django.core.mail import (
-    EmailMessage, EmailMultiAlternatives, SafeMIMEMultipart,
-)
-from django.core.mail.message import SafeMIMEMessage, SafeMIMEText
+from django.core.mail import EmailMultiAlternatives, SafeMIMEMultipart
+from django.core.mail.message import SafeMIMEText
 from django.db import connection, transaction
 from django.db.models import Q
 from django.dispatch import receiver
 from django.template.loader import get_template
-from django.utils.encoding import force_bytes
 from django.utils.html import escape
 from django.utils.timezone import now, override
 from django.utils.translation import gettext as _, pgettext
@@ -389,25 +382,15 @@ def mail(email: Union[str, Sequence[str]], subject: Union[str, FormattedString],
 class CustomEmail(EmailMultiAlternatives):
     def _create_mime_attachment(self, content, mimetype):
         """
-        Modified version of EmailMessage._create_mime_attachment that supports multiparts and
-        never generates plaintext attachments.
+        Convert the content, mimetype pair into a MIME attachment object.
+
+        If the mimetype is message/rfc822, content may be an
+        email.Message or EmailMessage object, as well as a str.
         """
         basetype, subtype = mimetype.split('/', 1)
         if basetype == 'multipart' and isinstance(content, SafeMIMEMultipart):
-            attachment = content
-        # START: VENDORED FROM EmailMessage #
-        elif basetype == "message" and subtype == "rfc822":
-            if isinstance(content, EmailMessage):
-                content = content.message()
-            elif not isinstance(content, Message):
-                content = message_from_bytes(force_bytes(content))
-            attachment = SafeMIMEMessage(content, subtype)
-        else:
-            attachment = MIMEBase(basetype, subtype)
-            attachment.set_payload(content)
-            encoders.encode_base64(attachment)
-        return attachment
-        # END: VENDORED FROM EmailMessage #
+            return content
+        return super()._create_mime_attachment(content, mimetype)
 
 
 @app.task(base=TransactionAwareTask, bind=True, acks_late=True)