diff --git a/src/cpp/model/gradido/TransactionTransfer.cpp b/src/cpp/model/gradido/TransactionTransfer.cpp
index 26442a4a1..6dfff3c6e 100644
--- a/src/cpp/model/gradido/TransactionTransfer.cpp
+++ b/src/cpp/model/gradido/TransactionTransfer.cpp
@@ -197,6 +197,7 @@ namespace model {
 				auto outbound_transfer = mProtoTransfer.outbound();
 				return outbound_transfer.other_group();
 			}
+			return "<unkown>";
 		}
 
 		Poco::AutoPtr<Transaction> TransactionTransfer::createOutbound(const std::string& memo)
diff --git a/src/cpp/model/table/ModelBase.h b/src/cpp/model/table/ModelBase.h
index d9087dcbd..2c62d6528 100644
--- a/src/cpp/model/table/ModelBase.h
+++ b/src/cpp/model/table/ModelBase.h
@@ -35,6 +35,7 @@ namespace model {
 			virtual ~ModelBase();
 
 			virtual const char* getTableName() const = 0;
+			//! called from within of some catch to give more information for debugging, don't lock mutex!
 			virtual std::string toString() = 0;
 			
 			template<class T> 
@@ -122,9 +123,9 @@ namespace model {
 			auto session = cm->getConnection(CONNECTION_MYSQL_LOGIN_SERVER);
 			Poco::Data::Statement select(session);
 			size_t count = 0;
-			select 
+			select
 				<< "SELECT count(id) from " << getTableName()
-				<< " where " << fieldName << " LIKE ? group by group_id"
+				<< " where " << fieldName << " LIKE ? group by " << fieldName
 				,Poco::Data::Keywords::into(count)
 				,Poco::Data::Keywords::useRef(fieldValue);
 
diff --git a/src/cpp/model/table/PendingTask.cpp b/src/cpp/model/table/PendingTask.cpp
index b33f2683a..bce0bb7f6 100644
--- a/src/cpp/model/table/PendingTask.cpp
+++ b/src/cpp/model/table/PendingTask.cpp
@@ -69,7 +69,9 @@ namespace model
 			ss << "id: " << mID << std::endl;
 			ss << "user_id: " << mUserId << std::endl;
 			ss << "created: " << Poco::DateTimeFormatter::format(mCreated, "%f.%m.%Y %H:%M:%S") << std::endl;
-			ss << "task type: " << typeToString((TaskType)mTaskTypeId);
+			ss << "task type: " << typeToString((TaskType)mTaskTypeId) << std::endl;
+			ss << "child pending task id: " << std::to_string(mChildPendingTaskId) << std::endl;
+			ss << "parent pending task id: " << std::to_string(mParentPendingTaskId) << std::endl;
 			return ss.str();
 		}
 
@@ -138,7 +140,6 @@ namespace model
 		Poco::Data::Statement PendingTask::_loadIdFromDB(Poco::Data::Session session)
 		{
 			Poco::Data::Statement select(session);
-			Poco::ScopedLock<Poco::Mutex> _lock(mWorkMutex);
 
 			select << "SELECT id FROM " << getTableName()
 				<< " WHERE user_id = ? "
@@ -155,7 +156,6 @@ namespace model
 		Poco::Data::Statement PendingTask::_insertIntoDB(Poco::Data::Session session)
 		{
 			Poco::Data::Statement insert(session);
-			Poco::ScopedLock<Poco::Mutex> _lock(mWorkMutex);
 
 			insert << "INSERT INTO " << getTableName()
 				<< " (user_id, hedera_id, request, created, task_type_id, child_pending_task_id, parent_pending_task_id) VALUES(?,?,?,?,?,?,?)"