diff --git a/backend/sync_server/src/errors.rs b/backend/sync_server/src/errors.rs
index 4f36824..ff6ff3c 100644
--- a/backend/sync_server/src/errors.rs
+++ b/backend/sync_server/src/errors.rs
@@ -2,7 +2,11 @@ use aide::OperationOutput;
 use axum::{
     http::StatusCode,
     response::{IntoResponse, Response},
+    Json,
 };
+use log::{info, warn};
+use schemars::JsonSchema;
+use serde::Serialize;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
@@ -10,33 +14,70 @@ pub enum SyncServerError {
     #[error("Initialisation error: {0}")]
     InitError(#[source] anyhow::Error),
 
-    #[error("Client error: {0}")]
+    #[error("Client error: {0:?}")]
     ClientError(#[source] anyhow::Error),
 
-    #[error("Server error: {0}")]
+    #[error("Server error: {0:?}")]
     ServerError(#[source] anyhow::Error),
 
     #[error("Not found: {0}")]
     NotFound(#[source] anyhow::Error),
 
-    #[error("Permission denier error: {0}")]
+    #[error("Unauthorized: {0}")]
+    Unauthorized(#[source] anyhow::Error),
+
+    #[error("Permission denied error: {0}")]
     PermissionDeniedError(#[source] anyhow::Error),
 }
 
+impl SyncServerError {
+    pub fn serialize(&self) -> SerializedError {
+        match self {
+            Self::InitError(error) => format_anyhow_error(error),
+            Self::ClientError(error) => format_anyhow_error(error),
+            Self::ServerError(error) => format_anyhow_error(error),
+            Self::NotFound(error) => format_anyhow_error(error),
+            Self::Unauthorized(error) => format_anyhow_error(error),
+            Self::PermissionDeniedError(error) => format_anyhow_error(error),
+        }
+    }
+}
+
 impl IntoResponse for SyncServerError {
     fn into_response(self) -> Response {
-        let body = self.to_string();
+        let body = Json(self.serialize());
 
         match self {
             Self::InitError(_) => (StatusCode::INTERNAL_SERVER_ERROR, body).into_response(),
             Self::ClientError(_) => (StatusCode::BAD_REQUEST, body).into_response(),
             Self::ServerError(_) => (StatusCode::INTERNAL_SERVER_ERROR, body).into_response(),
             Self::NotFound(_) => (StatusCode::NOT_FOUND, body).into_response(),
+            Self::Unauthorized(_) => (StatusCode::UNAUTHORIZED, body).into_response(),
             Self::PermissionDeniedError(_) => (StatusCode::FORBIDDEN, body).into_response(),
         }
     }
 }
 
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct SerializedError {
+    pub message: String,
+    pub causes: Vec<String>,
+}
+
+fn format_anyhow_error(error: &anyhow::Error) -> SerializedError {
+    let mut causes = vec![];
+    let mut current_error = error.source();
+    while let Some(error) = current_error {
+        causes.push(error.to_string());
+        current_error = error.source();
+    }
+
+    SerializedError {
+        message: error.to_string(),
+        causes,
+    }
+}
+
 impl OperationOutput for SyncServerError {
     type Inner = Self;
 }
@@ -46,17 +87,26 @@ pub fn init_error(error: anyhow::Error) -> SyncServerError {
 }
 
 pub fn server_error(error: anyhow::Error) -> SyncServerError {
+    warn!("Server error: {:?}", error);
     SyncServerError::ServerError(error)
 }
 
 pub fn client_error(error: anyhow::Error) -> SyncServerError {
+    info!("Client error: {:?}", error);
     SyncServerError::ClientError(error)
 }
 
 pub fn not_found_error(error: anyhow::Error) -> SyncServerError {
+    info!("Not found error: {:?}", error);
     SyncServerError::NotFound(error)
 }
 
+pub fn unauthorized_error(error: anyhow::Error) -> SyncServerError {
+    info!("Unauthorized error: {:?}", error);
+    SyncServerError::Unauthorized(error)
+}
+
 pub fn permission_denied_error(error: anyhow::Error) -> SyncServerError {
+    info!("Permission denied error: {:?}", error);
     SyncServerError::PermissionDeniedError(error)
 }