diff --git a/BMA.EHR.Application/Repositories/MinIODisciplineService.cs b/BMA.EHR.Application/Repositories/MinIODisciplineService.cs
index 25a9070d..cced52c4 100644
--- a/BMA.EHR.Application/Repositories/MinIODisciplineService.cs
+++ b/BMA.EHR.Application/Repositories/MinIODisciplineService.cs
@@ -1,4 +1,4 @@
-using Amazon.S3;
+using Amazon.S3;
 using Amazon.S3.Model;
 using BMA.EHR.Domain.Shared;
 using Microsoft.AspNetCore.Hosting;
@@ -37,7 +37,9 @@ namespace BMA.EHR.Application.Repositories
             var config = new AmazonS3Config
             {
                 ServiceURL = _configuration["MinIO:Endpoint"],
-                ForcePathStyle = true
+                ForcePathStyle = true,
+                SignatureVersion = "V4", // รองรับ MinIO
+                AuthenticationRegion = "th-middle-rack-1" // บาง MinIO ใช้ region "us-east-1" โดย default
             };
 
             _s3Client = new AmazonS3Client(_configuration["MinIO:AccessKey"], _configuration["MinIO:SecretKey"], config);
diff --git a/BMA.EHR.Application/Repositories/MinIOExamService.cs b/BMA.EHR.Application/Repositories/MinIOExamService.cs
index 38ff70d8..b800abb4 100644
--- a/BMA.EHR.Application/Repositories/MinIOExamService.cs
+++ b/BMA.EHR.Application/Repositories/MinIOExamService.cs
@@ -1,4 +1,4 @@
-using Amazon.S3;
+using Amazon.S3;
 using Amazon.S3.Model;
 using BMA.EHR.Domain.Models.Documents;
 using BMA.EHR.Domain.Shared;
@@ -40,7 +40,9 @@ namespace BMA.EHR.Application.Repositories
             var config = new AmazonS3Config
             {
                 ServiceURL = _configuration["MinIO:Endpoint"],
-                ForcePathStyle = true
+                ForcePathStyle = true,
+                SignatureVersion = "V4", // รองรับ MinIO
+                AuthenticationRegion = "th-middle-rack-1" // บาง MinIO ใช้ region "us-east-1" โดย default
             };
 
             _s3Client = new AmazonS3Client(_configuration["MinIO:AccessKey"], _configuration["MinIO:SecretKey"], config);
diff --git a/BMA.EHR.Application/Repositories/MinIOLeaveService.cs b/BMA.EHR.Application/Repositories/MinIOLeaveService.cs
index f2a30657..71c810a6 100644
--- a/BMA.EHR.Application/Repositories/MinIOLeaveService.cs
+++ b/BMA.EHR.Application/Repositories/MinIOLeaveService.cs
@@ -43,7 +43,9 @@ namespace BMA.EHR.Application.Repositories
             var config = new AmazonS3Config
             {
                 ServiceURL = _configuration["MinIO:Endpoint"],
-                ForcePathStyle = true
+                ForcePathStyle = true,
+                SignatureVersion = "V4", // รองรับ MinIO
+                AuthenticationRegion = "th-middle-rack-1" // บาง MinIO ใช้ region "us-east-1" โดย default
             };
 
             _s3Client = new AmazonS3Client(_configuration["MinIO:AccessKey"], _configuration["MinIO:SecretKey"], config);
diff --git a/BMA.EHR.Application/Repositories/MinIOService.cs b/BMA.EHR.Application/Repositories/MinIOService.cs
index fd07807b..ea470b27 100644
--- a/BMA.EHR.Application/Repositories/MinIOService.cs
+++ b/BMA.EHR.Application/Repositories/MinIOService.cs
@@ -1,4 +1,4 @@
-using Amazon.S3;
+using Amazon.S3;
 using Amazon.S3.Model;
 using BMA.EHR.Application.Common.Interfaces;
 using BMA.EHR.Domain.Models.Documents;
@@ -39,7 +39,9 @@ namespace BMA.EHR.Application.Repositories
             var config = new AmazonS3Config
             {
                 ServiceURL = _configuration["MinIO:Endpoint"],
-                ForcePathStyle = true
+                ForcePathStyle = true,
+                SignatureVersion = "V4", // รองรับ MinIO
+                AuthenticationRegion = "th-middle-rack-1" // บาง MinIO ใช้ region "us-east-1" โดย default
             };
 
             _s3Client = new AmazonS3Client(_configuration["MinIO:AccessKey"], _configuration["MinIO:SecretKey"], config);