diff --git a/bindings/matrix-sdk-ffi/src/client_builder.rs b/bindings/matrix-sdk-ffi/src/client_builder.rs
index 26d79340a..c67f679dc 100644
--- a/bindings/matrix-sdk-ffi/src/client_builder.rs
+++ b/bindings/matrix-sdk-ffi/src/client_builder.rs
@@ -71,7 +71,7 @@ pub enum ClientBuildError {
     #[error(transparent)]
     ServerUnreachable(HttpError),
     #[error(transparent)]
-    WellKnownLookupFailed(RumaApiError),
+    WellKnownLookupFailed(Box<RumaApiError>),
     #[error(transparent)]
     WellKnownDeserializationError(DeserializationError),
     #[error(transparent)]
@@ -94,12 +94,15 @@ impl From<MatrixClientBuildError> for ClientBuildError {
         match e {
             MatrixClientBuildError::InvalidServerName => ClientBuildError::InvalidServerName,
             MatrixClientBuildError::Http(e) => ClientBuildError::ServerUnreachable(e),
-            MatrixClientBuildError::AutoDiscovery(FromHttpResponseError::Server(e)) => {
-                ClientBuildError::WellKnownLookupFailed(e)
-            }
-            MatrixClientBuildError::AutoDiscovery(FromHttpResponseError::Deserialization(e)) => {
-                ClientBuildError::WellKnownDeserializationError(e)
-            }
+            MatrixClientBuildError::AutoDiscovery(e) => match *e {
+                FromHttpResponseError::Server(e) => {
+                    ClientBuildError::WellKnownLookupFailed(Box::new(e))
+                }
+                FromHttpResponseError::Deserialization(e) => {
+                    ClientBuildError::WellKnownDeserializationError(e)
+                }
+                _ => ClientBuildError::Sdk(MatrixClientBuildError::AutoDiscovery(e)),
+            },
             MatrixClientBuildError::SlidingSyncVersion(e) => {
                 ClientBuildError::SlidingSyncVersion(e)
             }
diff --git a/crates/matrix-sdk/src/authentication/oauth/qrcode/grant.rs b/crates/matrix-sdk/src/authentication/oauth/qrcode/grant.rs
index 20a73d832..229f812dd 100644
--- a/crates/matrix-sdk/src/authentication/oauth/qrcode/grant.rs
+++ b/crates/matrix-sdk/src/authentication/oauth/qrcode/grant.rs
@@ -76,7 +76,7 @@ async fn finish_login_grant<Q>(
         message => {
             return Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.protocol",
-                received: message,
+                received: Box::new(message),
             });
         }
     };
@@ -140,7 +140,7 @@ async fn finish_login_grant<Q>(
         message => {
             return Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.success",
-                received: message,
+                received: Box::new(message),
             });
         }
     }
@@ -1287,13 +1287,17 @@ mod test {
         });
 
         // Wait for all tasks to finish / fail.
-        assert_matches!(
-            grant.await,
+        assert_let!(
             Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.protocol",
-                received: QrAuthMessage::LoginSuccess
-            }),
-            "Alice should abort the login with expected error"
+                received,
+            }) = grant.await,
+            "Alice should abort the login with expected error variant"
+        );
+        assert_matches!(
+            *received,
+            QrAuthMessage::LoginSuccess,
+            "Alice should abort the login with expected error message"
         );
         updates_task.await.expect("Alice should run through all progress states");
         bob_task.await.expect("Bob's task should finish");
@@ -1398,13 +1402,17 @@ mod test {
         });
 
         // Wait for all tasks to finish / fail.
-        assert_matches!(
-            grant.await,
+        assert_let!(
             Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.protocol",
-                received: QrAuthMessage::LoginSuccess
-            }),
-            "Alice should abort the login with expected error"
+                received,
+            }) = grant.await,
+            "Alice should abort the login with expected error variant"
+        );
+        assert_matches!(
+            *received,
+            QrAuthMessage::LoginSuccess,
+            "Alice should abort the login with expected error message"
         );
         updates_task.await.expect("Alice should run through all progress states");
         bob_task.await.expect("Bob's task should finish");
@@ -2711,13 +2719,17 @@ mod test {
         });
 
         // Wait for all tasks to finish / fail.
-        assert_matches!(
-            grant.await,
+        assert_let!(
             Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.success",
-                received: QrAuthMessage::LoginProtocolAccepted
-            }),
-            "Alice should abort the login with expected error"
+                received,
+            }) = grant.await,
+            "Alice should abort the login with expected error variant"
+        );
+        assert_matches!(
+            *received,
+            QrAuthMessage::LoginProtocolAccepted,
+            "Alice should abort the login with expected error message"
         );
         updates_task.await.expect("Alice should run through all progress states");
         bob_task.await.expect("Bob's task should finish");
@@ -2840,13 +2852,17 @@ mod test {
         });
 
         // Wait for all tasks to finish / fail.
-        assert_matches!(
-            grant.await,
+        assert_let!(
             Err(QRCodeGrantLoginError::UnexpectedMessage {
                 expected: "m.login.success",
-                received: QrAuthMessage::LoginProtocolAccepted
-            }),
-            "Alice should abort the login with expected error"
+                received,
+            }) = grant.await,
+            "Alice should abort the login with expected error variant"
+        );
+        assert_matches!(
+            *received,
+            QrAuthMessage::LoginProtocolAccepted,
+            "Alice should abort the login with expected error message"
         );
         updates_task.await.expect("Alice should run through all progress states");
         bob_task.await.expect("Bob's task should finish");
diff --git a/crates/matrix-sdk/src/authentication/oauth/qrcode/login.rs b/crates/matrix-sdk/src/authentication/oauth/qrcode/login.rs
index a642aeddb..24d3a3885 100644
--- a/crates/matrix-sdk/src/authentication/oauth/qrcode/login.rs
+++ b/crates/matrix-sdk/src/authentication/oauth/qrcode/login.rs
@@ -97,7 +97,7 @@ async fn finish_login<Q>(
 
             return Err(QRCodeLoginError::UnexpectedMessage {
                 expected: "m.login.protocol_accepted",
-                received: message,
+                received: Box::new(message),
             });
         }
     }
@@ -176,7 +176,7 @@ async fn finish_login<Q>(
 
             return Err(QRCodeLoginError::UnexpectedMessage {
                 expected: "m.login.secrets",
-                received: message,
+                received: Box::new(message),
             });
         }
     };
@@ -410,7 +410,7 @@ impl<'a> IntoFuture for LoginWithGeneratedQrCode<'a> {
 
                     return Err(QRCodeLoginError::UnexpectedMessage {
                         expected: "m.login.protocols",
-                        received: message,
+                        received: Box::new(message),
                     });
                 }
             };
diff --git a/crates/matrix-sdk/src/authentication/oauth/qrcode/mod.rs b/crates/matrix-sdk/src/authentication/oauth/qrcode/mod.rs
index c1af524b1..c9b4ddcd2 100644
--- a/crates/matrix-sdk/src/authentication/oauth/qrcode/mod.rs
+++ b/crates/matrix-sdk/src/authentication/oauth/qrcode/mod.rs
@@ -81,7 +81,7 @@ pub enum QRCodeLoginError {
         /// The message we expected.
         expected: &'static str,
         /// The message we received instead.
-        received: QrAuthMessage,
+        received: Box<QrAuthMessage>,
     },
 
     /// An error happened while exchanging messages with the other device.
@@ -178,7 +178,7 @@ pub enum QRCodeGrantLoginError {
         /// The message we expected.
         expected: &'static str,
         /// The message we received instead.
-        received: QrAuthMessage,
+        received: Box<QrAuthMessage>,
     },
 
     /// The other device has signaled to us that the login has failed.
diff --git a/crates/matrix-sdk/src/client/builder/homeserver_config.rs b/crates/matrix-sdk/src/client/builder/homeserver_config.rs
index 2c1c3b8e2..d6167c664 100644
--- a/crates/matrix-sdk/src/client/builder/homeserver_config.rs
+++ b/crates/matrix-sdk/src/client/builder/homeserver_config.rs
@@ -187,7 +187,7 @@ async fn discover_homeserver(
         )
         .await
         .map_err(|e| match e {
-            HttpError::Api(err) => ClientBuildError::AutoDiscovery(*err),
+            HttpError::Api(err) => ClientBuildError::AutoDiscovery(err),
             err => ClientBuildError::Http(err),
         })?;
 
diff --git a/crates/matrix-sdk/src/client/builder/mod.rs b/crates/matrix-sdk/src/client/builder/mod.rs
index 16e4c23a0..cf2ba9980 100644
--- a/crates/matrix-sdk/src/client/builder/mod.rs
+++ b/crates/matrix-sdk/src/client/builder/mod.rs
@@ -856,7 +856,7 @@ pub enum ClientBuildError {
 
     /// Error looking up the .well-known endpoint on auto-discovery
     #[error("Error looking up the .well-known endpoint on auto-discovery")]
-    AutoDiscovery(FromHttpResponseError<RumaApiError>),
+    AutoDiscovery(Box<FromHttpResponseError<RumaApiError>>),
 
     /// Error when building the sliding sync version.
     #[error(transparent)]
@@ -961,7 +961,8 @@ pub(crate) mod tests {
         let error = builder.build().await.unwrap_err();
 
         // Then the operation should fail with a server discovery error.
-        assert_matches!(error, ClientBuildError::AutoDiscovery(FromHttpResponseError::Server(_)));
+        assert_let!(ClientBuildError::AutoDiscovery(e) = error);
+        assert_matches!(*e, FromHttpResponseError::Server(_));
     }
 
     #[async_test]
@@ -998,10 +999,8 @@ pub(crate) mod tests {
         let error = builder.build().await.unwrap_err();
 
         // Then the operation should fail due to the well-known file's contents.
-        assert_matches!(
-            error,
-            ClientBuildError::AutoDiscovery(FromHttpResponseError::Deserialization(_))
-        );
+        assert_let!(ClientBuildError::AutoDiscovery(e) = error);
+        assert_matches!(*e, FromHttpResponseError::Deserialization(_));
     }
 
     #[async_test]