diff --git a/src/pretix/_base_settings.py b/src/pretix/_base_settings.py
index e38e844ae9..1fc7d029cd 100644
--- a/src/pretix/_base_settings.py
+++ b/src/pretix/_base_settings.py
@@ -296,7 +296,7 @@ PILLOW_FORMATS_QUESTIONS_IMAGE = ('PNG', 'GIF', 'JPEG', 'BMP', 'TIFF')
 FILE_UPLOAD_EXTENSIONS_EMAIL_ATTACHMENT = (
     ".png", ".jpg", ".gif", ".jpeg", ".pdf", ".txt", ".docx", ".gif", ".svg",
     ".pptx", ".ppt", ".doc", ".xlsx", ".xls", ".jfif", ".heic", ".heif", ".pages",
-    ".bmp", ".tif", ".tiff"
+    ".bmp", ".tif", ".tiff", ".ics",
 )
 FILE_UPLOAD_EXTENSIONS_OTHER = FILE_UPLOAD_EXTENSIONS_EMAIL_ATTACHMENT