diff --git a/modules/features/teamsbot/service.py b/modules/features/teamsbot/service.py
index af3f0686..a3d9bef6 100644
--- a/modules/features/teamsbot/service.py
+++ b/modules/features/teamsbot/service.py
@@ -281,7 +281,7 @@ class TeamsbotService:
             sessionId=sessionId,
             speaker=speaker,
             text=transcriptText,
-            timestamp=getUtcTimestamp(),
+            timestamp=str(getUtcTimestamp()),
             confidence=confidence,
             language=self.config.language,
             isFinal=True,
@@ -476,7 +476,7 @@ class TeamsbotService:
                     modelName=response.modelName,
                     processingTime=response.processingTime,
                     priceCHF=response.priceCHF,
-                    timestamp=getUtcTimestamp(),
+                    timestamp=str(getUtcTimestamp()),
                 ).model_dump()
 
                 createdResponse = interface.createBotResponse(botResponseData)