diff --git a/Cargo.lock b/Cargo.lock
index f7be5e1..7155be6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3036,7 +3036,7 @@ dependencies = [
 
 [[package]]
 name = "py_chrontext"
-version = "0.9.10"
+version = "0.9.11"
 dependencies = [
  "chrontext",
  "env_logger",
diff --git a/lib/flight/src/client.rs b/lib/flight/src/client.rs
index e8def33..2acf8bc 100644
--- a/lib/flight/src/client.rs
+++ b/lib/flight/src/client.rs
@@ -9,11 +9,11 @@ use query_processing::errors::QueryProcessingError;
 use query_processing::graph_patterns::union;
 use representation::solution_mapping::SolutionMappings;
 use representation::RDFNodeType;
+use secrecy::{ExposeSecret, SecretString};
 use std::collections::HashMap;
 use std::str::FromStr;
-use std::time::Duration;
-use secrecy::{ExposeSecret, SecretString};
 use thiserror::*;
+use tonic::metadata::MetadataKey;
 use tonic::transport::{Channel, Endpoint};
 use tonic::{Request, Status};
 
@@ -63,8 +63,11 @@ impl ChrontextFlightClient {
         };
         info!("Building request");
         let mut request = Request::new(Ticket::new(serialize(query).unwrap()));
-        for (k,v) in metadata {
-            request.metadata_mut().insert(k, v.expose_secret().parse().unwrap());
+        for (k, v) in metadata {
+            request.metadata_mut().insert(
+                MetadataKey::from_str(k).unwrap().to_owned(),
+                v.expose_secret().parse().unwrap(),
+            );
         }
         info!("Sending request");
         let mut flight_data = client
diff --git a/py_chrontext/Cargo.toml b/py_chrontext/Cargo.toml
index 621d2ae..faecbb4 100644
--- a/py_chrontext/Cargo.toml
+++ b/py_chrontext/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "py_chrontext"
-version = "0.9.10"
+version = "0.9.11"
 edition = "2021"
 
 [dependencies]