diff --git a/LeStorage/ApiCallCollection.swift b/LeStorage/ApiCallCollection.swift
index e9b74fb..8e8fe59 100644
--- a/LeStorage/ApiCallCollection.swift
+++ b/LeStorage/ApiCallCollection.swift
@@ -19,6 +19,10 @@ protocol SomeCallCollection {
 
 }
 
+enum ApiCallError: Error {
+    case cantCreateCall
+}
+
 /// ApiCallCollection is an object communicating with a server to synchronize data managed locally
 /// The Api calls are serialized and stored in a JSON file
 /// Failing Api calls are stored forever and will be executed again later
@@ -227,12 +231,17 @@ actor ApiCallCollection<T: Storable>: SomeCallCollection {
 
     /// Creates an API call for the Storable [instance] and an HTTP [method]
     fileprivate func _createCall(_ instance: T, method: HTTPMethod) throws -> ApiCall<T> {
-        let jsonString = try instance.jsonString()
-        return ApiCall(method: method, dataId: instance.stringId, body: jsonString)
+        do {
+            let jsonString = try instance.jsonString()
+            return ApiCall(method: method, dataId: instance.stringId, body: jsonString)
+        } catch {
+            StoreCenter.main.log(message: "call could not be created for \(T.resourceName()): \(error.localizedDescription)")
+            throw ApiCallError.cantCreateCall
+        }
     }
 
     /// Prepares a call for execution by updating its properties and adding it to its collection for storage
-    fileprivate func _prepareCall(apiCall: ApiCall<T>) throws {
+    fileprivate func _prepareCall(apiCall: ApiCall<T>) {
         apiCall.lastAttemptDate = Date()
         apiCall.attemptsCount += 1
         self.addOrUpdate(apiCall)
@@ -244,6 +253,7 @@ actor ApiCallCollection<T: Storable>: SomeCallCollection {
             return try await self._synchronize(instance, method: HTTPMethod.post)
         } catch {
             self.rescheduleApiCallsIfNecessary()
+            StoreCenter.main.log(message: "POST failed for \(instance)")
             Logger.error(error)
         }
         return nil
@@ -256,6 +266,7 @@ actor ApiCallCollection<T: Storable>: SomeCallCollection {
             return try await self._synchronize(instance, method: HTTPMethod.put)
         } catch {
             self.rescheduleApiCallsIfNecessary()
+            StoreCenter.main.log(message: "PUT failed for \(instance)")
             Logger.error(error)
         }
         return nil
@@ -267,6 +278,7 @@ actor ApiCallCollection<T: Storable>: SomeCallCollection {
             let _: Empty? = try await self._synchronize(instance, method: HTTPMethod.delete)
         } catch {
             self.rescheduleApiCallsIfNecessary()
+            StoreCenter.main.log(message: "DELETE failed for \(instance)")
             Logger.error(error)
         }
         return
@@ -275,7 +287,7 @@ actor ApiCallCollection<T: Storable>: SomeCallCollection {
     /// Initiates the process of sending the data with the server
     fileprivate func _synchronize<V: Decodable>(_ instance: T, method: HTTPMethod) async throws -> V? {
         if let apiCall = try self._callForInstance(instance, method: method) {
-            try self._prepareCall(apiCall: apiCall)
+            self._prepareCall(apiCall: apiCall)
             return try await self._executeApiCall(apiCall)
         } else {
             return nil
diff --git a/LeStorage/Services.swift b/LeStorage/Services.swift
index 4fd0be2..d6df69c 100644
--- a/LeStorage/Services.swift
+++ b/LeStorage/Services.swift
@@ -121,7 +121,7 @@ public class Services {
             print("\(debugURL) ended, status code = \(statusCode)")
             switch statusCode {
             case 200..<300: // success
-                    try await StoreCenter.main.deleteApiCallById(type: T.self, id: apiCall.id)
+                try await StoreCenter.main.deleteApiCallById(type: T.self, id: apiCall.id)
             default: // error
                 Logger.log("Failed Run \(request.httpMethod ?? "") \(request.url?.absoluteString ?? "")")
                 let errorString: String = String(data: task.0, encoding: .utf8) ?? ""
diff --git a/LeStorage/StoredCollection.swift b/LeStorage/StoredCollection.swift
index 982bab5..849b493 100644
--- a/LeStorage/StoredCollection.swift
+++ b/LeStorage/StoredCollection.swift
@@ -399,14 +399,13 @@ public class StoredCollection<T: Storable>: RandomAccessCollection, SomeCollecti
     
     /// Writes all the items as a json array inside a file
     fileprivate func _write() {
-//        Logger.log("Start write to \(T.fileName())...")
         do {
             let jsonString: String = try self.items.jsonString()
             try self._store.write(content: jsonString, fileName: T.fileName())
         } catch {
-            Logger.error(error) // TODO how to notify the main project
+            Logger.error(error)
+            StoreCenter.main.log(message: "write failed for \(T.resourceName()): \(error.localizedDescription)")
         }
-//        Logger.log("End write")
     }
     
     /// Simply clears the items of the collection