diff --git a/backend/mpc-system/services/server-party/application/use_cases/participate_keygen.go b/backend/mpc-system/services/server-party/application/use_cases/participate_keygen.go
index 70db6862..82b4f763 100644
--- a/backend/mpc-system/services/server-party/application/use_cases/participate_keygen.go
+++ b/backend/mpc-system/services/server-party/application/use_cases/participate_keygen.go
@@ -121,7 +121,15 @@ func (uc *ParticipateKeygenUseCase) Execute(
 		if p.PartyID == input.PartyID {
 			selfIndex = p.PartyIndex
 		}
+		logger.Debug("Added participant to index map",
+			zap.String("party_id", p.PartyID),
+			zap.Int("party_index", p.PartyIndex))
 	}
+	logger.Info("Built party index map",
+		zap.String("session_id", input.SessionID.String()),
+		zap.String("self_party_id", input.PartyID),
+		zap.Int("self_index", selfIndex),
+		zap.Int("total_participants", len(sessionInfo.Participants)))
 
 	// 3. Subscribe to messages
 	msgChan, err := uc.messageRouter.SubscribeMessages(ctx, input.SessionID, input.PartyID)
@@ -303,16 +311,28 @@ func (h *keygenMessageHandler) convertMessages(ctx context.Context, inChan <-cha
 	for {
 		select {
 		case <-ctx.Done():
+			logger.Debug("convertMessages context cancelled", zap.String("session_id", h.sessionID.String()))
 			close(h.msgChan)
 			return
 		case msg, ok := <-inChan:
 			if !ok {
+				logger.Debug("convertMessages inChan closed", zap.String("session_id", h.sessionID.String()))
 				close(h.msgChan)
 				return
 			}
 
+			logger.Debug("Received MPC message for conversion",
+				zap.String("session_id", h.sessionID.String()),
+				zap.String("from_party", msg.FromParty),
+				zap.Bool("is_broadcast", msg.IsBroadcast),
+				zap.Int("payload_size", len(msg.Payload)))
+
 			fromIndex, exists := h.partyIndexMap[msg.FromParty]
 			if !exists {
+				logger.Warn("Message from unknown party - dropping",
+					zap.String("session_id", h.sessionID.String()),
+					zap.String("from_party", msg.FromParty),
+					zap.Any("known_parties", h.partyIndexMap))
 				continue
 			}
 
@@ -322,8 +342,15 @@ func (h *keygenMessageHandler) convertMessages(ctx context.Context, inChan <-cha
 				MsgBytes:       msg.Payload,
 			}
 
+			logger.Debug("Converted message, sending to TSS",
+				zap.String("session_id", h.sessionID.String()),
+				zap.String("from_party", msg.FromParty),
+				zap.Int("from_index", fromIndex))
+
 			select {
 			case h.msgChan <- tssMsg:
+				logger.Debug("Message sent to TSS successfully",
+					zap.String("session_id", h.sessionID.String()))
 			case <-ctx.Done():
 				return
 			}