diff --git a/client-v2/src/main/java/com/clickhouse/client/api/Client.java b/client-v2/src/main/java/com/clickhouse/client/api/Client.java
index c747904f6..3edf74ba8 100644
--- a/client-v2/src/main/java/com/clickhouse/client/api/Client.java
+++ b/client-v2/src/main/java/com/clickhouse/client/api/Client.java
@@ -1197,7 +1197,7 @@ public CompletableFuture<InsertResponse> insert(String tableName, List<?> data,
         Integer retry = (Integer) configuration.get(ClientConfigProperties.RETRY_ON_FAILURE.getKey());
         final int maxRetries = retry == null ? 0 : retry;
 
-        settings.setOption(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey(), format.name());
+        settings.setOption(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey(), format);
         final InsertSettings finalSettings = new InsertSettings(buildRequestSettings(settings.getAllSettings()));
         Supplier<InsertResponse> supplier = () -> {
             long startTime = System.nanoTime();
@@ -1400,7 +1400,7 @@ public CompletableFuture<InsertResponse> insert(String tableName,
             throw new IllegalArgumentException("Buffer size must be greater than 0");
         }
 
-        settings.setOption(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey(), format.name());
+        settings.setOption(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey(), format);
         final InsertSettings finalSettings = new InsertSettings(buildRequestSettings(settings.getAllSettings()));
 
         StringBuilder sqlStmt = new StringBuilder("INSERT INTO ").append(tableName);
diff --git a/client-v2/src/main/java/com/clickhouse/client/api/internal/HttpAPIClientHelper.java b/client-v2/src/main/java/com/clickhouse/client/api/internal/HttpAPIClientHelper.java
index 94af7a11e..7f6f442f5 100644
--- a/client-v2/src/main/java/com/clickhouse/client/api/internal/HttpAPIClientHelper.java
+++ b/client-v2/src/main/java/com/clickhouse/client/api/internal/HttpAPIClientHelper.java
@@ -14,6 +14,7 @@
 import com.clickhouse.client.api.enums.ProxyType;
 import com.clickhouse.client.api.http.ClickHouseHttpProto;
 import com.clickhouse.client.api.transport.Endpoint;
+import com.clickhouse.data.ClickHouseFormat;
 import net.jpountz.lz4.LZ4Factory;
 import org.apache.hc.client5.http.ConnectTimeoutException;
 import org.apache.hc.client5.http.classic.methods.HttpPost;
@@ -64,6 +65,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Method;
 import java.net.ConnectException;
 import java.net.InetSocketAddress;
@@ -449,13 +451,13 @@ private void addHeaders(HttpPost req, Map<String, Object> requestConfig) {
             addHeader(
                 req,
                 ClickHouseHttpProto.HEADER_FORMAT,
-                requestConfig.get(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey()));
+                    ((ClickHouseFormat) requestConfig.get(ClientConfigProperties.INPUT_OUTPUT_FORMAT.getKey())).name());
         }
         if (requestConfig.containsKey(ClientConfigProperties.QUERY_ID.getKey())) {
             addHeader(
                 req,
                 ClickHouseHttpProto.HEADER_QUERY_ID,
-                requestConfig.get(ClientConfigProperties.QUERY_ID.getKey()));
+                    (String) requestConfig.get(ClientConfigProperties.QUERY_ID.getKey()));
         }
         addHeader(
             req,
@@ -757,21 +759,25 @@ public void close() {
     }
 
     private static <T> void addHeader(HttpRequest req, String headerName,
-        T value)
+        String value)
     {
         if (value == null) {
             return;
         }
-        String tString = value.toString();
-        if (tString.isBlank()) {
+
+        if (value.trim().isEmpty()) {
             return;
         }
-        if (PATTERN_HEADER_VALUE_ASCII.matcher(tString).matches()) {
-            req.addHeader(headerName, tString);
+        if (PATTERN_HEADER_VALUE_ASCII.matcher(value).matches()) {
+            req.addHeader(headerName, value);
         } else {
-            req.addHeader(
-                headerName + "*",
-                "UTF-8''" + URLEncoder.encode(tString, StandardCharsets.UTF_8));
+            try {
+                req.addHeader(
+                        headerName + "*",
+                        "UTF-8''" + URLEncoder.encode(value, StandardCharsets.UTF_8.name()));
+            } catch (UnsupportedEncodingException e) {
+                throw new ClientException("Failed to convert string to UTF8" , e);
+            }
         }
     }