diff --git a/application/src/main/java/org/thingsboard/server/service/ai/Langchain4jChatModelConfigurerImpl.java b/application/src/main/java/org/thingsboard/server/service/ai/Langchain4jChatModelConfigurerImpl.java
index 30942beda7..970e778a29 100644
--- a/application/src/main/java/org/thingsboard/server/service/ai/Langchain4jChatModelConfigurerImpl.java
+++ b/application/src/main/java/org/thingsboard/server/service/ai/Langchain4jChatModelConfigurerImpl.java
@@ -29,7 +29,6 @@ import dev.langchain4j.model.chat.ChatModel;
 import dev.langchain4j.model.chat.request.ChatRequestParameters;
 import dev.langchain4j.model.vertexai.gemini.VertexAiGeminiChatModel;
 import org.springframework.stereotype.Component;
-import org.thingsboard.common.util.JacksonUtil;
 import org.thingsboard.server.common.data.ai.model.chat.AmazonBedrockChatModel;
 import org.thingsboard.server.common.data.ai.model.chat.AnthropicChatModel;
 import org.thingsboard.server.common.data.ai.model.chat.AzureOpenAiChatModel;
@@ -113,9 +112,7 @@ class Langchain4jChatModelConfigurerImpl implements Langchain4jChatModelConfigur
         // construct service account credentials using service account key JSON
         ServiceAccountCredentials serviceAccountCredentials;
         try {
-            serviceAccountCredentials = ServiceAccountCredentials.fromStream(
-                    new ByteArrayInputStream(JacksonUtil.writeValueAsBytes(providerConfig.serviceAccountKey()))
-            );
+            serviceAccountCredentials = ServiceAccountCredentials.fromStream(new ByteArrayInputStream(providerConfig.serviceAccountKey().getBytes()));
         } catch (IOException e) {
             throw new RuntimeException("Failed to parse service account key JSON", e);
         }
diff --git a/common/data/src/main/java/org/thingsboard/server/common/data/ai/provider/GoogleVertexAiGeminiProviderConfig.java b/common/data/src/main/java/org/thingsboard/server/common/data/ai/provider/GoogleVertexAiGeminiProviderConfig.java
index a5140279ac..e714b7d371 100644
--- a/common/data/src/main/java/org/thingsboard/server/common/data/ai/provider/GoogleVertexAiGeminiProviderConfig.java
+++ b/common/data/src/main/java/org/thingsboard/server/common/data/ai/provider/GoogleVertexAiGeminiProviderConfig.java
@@ -15,12 +15,11 @@
  */
 package org.thingsboard.server.common.data.ai.provider;
 
-import com.fasterxml.jackson.databind.node.ObjectNode;
-
 public record GoogleVertexAiGeminiProviderConfig(
+        String fileName, // not used on BE, but needed for UI
         String projectId,
         String location,
-        ObjectNode serviceAccountKey
+        String serviceAccountKey
 ) implements AiProviderConfig {
 
     @Override