diff --git a/crates/caldav/src/calendar/methods/mkcalendar.rs b/crates/caldav/src/calendar/methods/mkcalendar.rs
index b7175e7..0b95231 100644
--- a/crates/caldav/src/calendar/methods/mkcalendar.rs
+++ b/crates/caldav/src/calendar/methods/mkcalendar.rs
@@ -72,12 +72,16 @@ pub async fn route_mkcalendar<C: CalendarStore, S: SubscriptionStore>(
         return Err(Error::Unauthorized);
     }
 
-    let request = match method.as_str() {
+    let mut request = match method.as_str() {
         "MKCALENDAR" => MkcalendarRequest::parse_str(&body)?.set.prop,
         "MKCOL" => MkcolRequest::parse_str(&body)?.set.prop,
         _ => unreachable!("We never call with another method"),
     };
 
+    if let Some("") = request.displayname.as_deref() {
+        request.displayname = None
+    }
+
     let calendar = Calendar {
         id: cal_id.to_owned(),
         principal: principal.to_owned(),
diff --git a/crates/carddav/src/addressbook/methods/mkcol.rs b/crates/carddav/src/addressbook/methods/mkcol.rs
index e640b65..61c6654 100644
--- a/crates/carddav/src/addressbook/methods/mkcol.rs
+++ b/crates/carddav/src/addressbook/methods/mkcol.rs
@@ -52,8 +52,10 @@ pub async fn route_mkcol<AS: AddressbookStore, S: SubscriptionStore>(
         return Err(Error::Unauthorized);
     }
 
-    let request = MkcolRequest::parse_str(&body)?;
-    let request = request.set.prop;
+    let mut request = MkcolRequest::parse_str(&body)?.set.prop;
+    if let Some("") = request.displayname.as_deref() {
+        request.displayname = None
+    }
 
     let addressbook = Addressbook {
         id: addressbook_id.to_owned(),