diff --git a/packages/server/src/api/controllers/Attachments/AttachmentsController.ts b/packages/server/src/api/controllers/Attachments/AttachmentsController.ts
index ba41db541..657aa0240 100644
--- a/packages/server/src/api/controllers/Attachments/AttachmentsController.ts
+++ b/packages/server/src/api/controllers/Attachments/AttachmentsController.ts
@@ -4,12 +4,16 @@ import { Router, Response, NextFunction, Request } from 'express';
 import { body, param } from 'express-validator';
 import BaseController from '@/api/controllers/BaseController';
 import { AttachmentsApplication } from '@/services/Attachments/AttachmentsApplication';
+import { AttachmentUploadPipeline } from '@/services/Attachments/S3UploadPipeline';
 
 @Service()
 export class AttachmentsController extends BaseController {
   @Inject()
   private attachmentsApplication: AttachmentsApplication;
 
+  @Inject()
+  private uploadPipelineService: AttachmentUploadPipeline;
+
   /**
    * Router constructor.
    */
@@ -18,7 +22,8 @@ export class AttachmentsController extends BaseController {
 
     router.post(
       '/',
-      this.attachmentsApplication.uploadPipeline.single('file'),
+      this.uploadPipelineService.validateS3Configured,
+      this.uploadPipelineService.uploadPipeline().single('file'),
       this.validateUploadedFileExistance,
       this.uploadAttachment.bind(this)
     );
diff --git a/packages/server/src/config/index.ts b/packages/server/src/config/index.ts
index a9e2212b1..8172ddace 100644
--- a/packages/server/src/config/index.ts
+++ b/packages/server/src/config/index.ts
@@ -235,6 +235,6 @@ module.exports = {
     accessKeyId: process.env.S3_ACCESS_KEY_ID,
     secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
     endpoint: process.env.S3_ENDPOINT,
-    bucket: process.env.S3_BUCKET,
+    bucket: process.env.S3_BUCKET || 'bigcapital-documents',
   },
 };
diff --git a/packages/server/src/services/Attachments/AttachmentsApplication.ts b/packages/server/src/services/Attachments/AttachmentsApplication.ts
index ce297d3ba..2cf7c08f1 100644
--- a/packages/server/src/services/Attachments/AttachmentsApplication.ts
+++ b/packages/server/src/services/Attachments/AttachmentsApplication.ts
@@ -2,11 +2,9 @@ import { Inject, Service } from 'typedi';
 import { UploadDocument } from './UploadDocument';
 import { DeleteAttachment } from './DeleteAttachment';
 import { GetAttachment } from './GetAttachment';
-import { AttachmentUploadPipeline } from './S3UploadPipeline';
 import { LinkAttachment } from './LinkAttachment';
 import { UnlinkAttachment } from './UnlinkAttachment';
 import { getAttachmentPresignedUrl } from './GetAttachmentPresignedUrl';
-import type { Multer } from 'multer';
 
 @Service()
 export class AttachmentsApplication {
@@ -19,9 +17,6 @@ export class AttachmentsApplication {
   @Inject()
   private getDocumentService: GetAttachment;
 
-  @Inject()
-  private uploadPipelineService: AttachmentUploadPipeline;
-
   @Inject()
   private linkDocumentService: LinkAttachment;
 
@@ -31,14 +26,6 @@ export class AttachmentsApplication {
   @Inject()
   private getPresignedUrlService: getAttachmentPresignedUrl;
 
-  /**
-   * Express middleware for uploading attachments to an S3 bucket.
-   * @returns {Multer}
-   */
-  get uploadPipeline(): Multer {
-    return this.uploadPipelineService.uploadPipeline();
-  }
-
   /**
    * Saves the metadata of uploaded document to S3 on database.
    * @param {number} tenantId
diff --git a/packages/server/src/services/Attachments/S3UploadPipeline.ts b/packages/server/src/services/Attachments/S3UploadPipeline.ts
index c79d2855f..b2443e318 100644
--- a/packages/server/src/services/Attachments/S3UploadPipeline.ts
+++ b/packages/server/src/services/Attachments/S3UploadPipeline.ts
@@ -1,12 +1,38 @@
 import multer from 'multer';
-import type { Multer } from 'multer'
+import type { Multer } from 'multer';
 import multerS3 from 'multer-s3';
 import { s3 } from '@/lib/S3/S3';
 import { Service } from 'typedi';
 import config from '@/config';
+import { NextFunction, Request, Response } from 'express';
 
 @Service()
 export class AttachmentUploadPipeline {
+  /**
+   * Middleware to ensure that S3 configuration is properly set before proceeding.
+   * This function checks if the necessary S3 configuration keys are present and throws an error if any are missing.
+   *
+   * @param req The HTTP request object.
+   * @param res The HTTP response object.
+   * @param next The callback to pass control to the next middleware function.
+   */
+  public validateS3Configured(req: Request, res: Response, next: NextFunction) {
+    if (
+      !config.s3.region ||
+      !config.s3.accessKeyId ||
+      !config.s3.secretAccessKey
+    ) {
+      const missingKeys = [];
+      if (!config.s3.region) missingKeys.push('region');
+      if (!config.s3.accessKeyId) missingKeys.push('accessKeyId');
+      if (!config.s3.secretAccessKey) missingKeys.push('secretAccessKey');
+      const missing = missingKeys.join(', ');
+
+      throw new Error(`S3 configuration error: Missing ${missing}`);
+    }
+    next();
+  }
+
   /**
    * Express middleware for uploading attachments to an S3 bucket.
    * It utilizes the multer middleware for handling multipart/form-data, specifically for file uploads.