diff --git a/keyserver/src/services/blob.js b/keyserver/src/services/blob.js
index f4e8b2bb6..f738ed587 100644
--- a/keyserver/src/services/blob.js
+++ b/keyserver/src/services/blob.js
@@ -1,135 +1,174 @@
 // @flow
 
 import blobService from 'lib/facts/blob-service.js';
 import {
   getBlobFetchableURL,
   makeBlobServiceEndpointURL,
 } from 'lib/utils/blob-service.js';
-import { getMessageForException } from 'lib/utils/errors.js';
 import { createHTTPAuthorizationHeader } from 'lib/utils/services-utils.js';
 
 import { verifyUserLoggedIn } from '../user/login.js';
 import { getContentSigningKey } from '../utils/olm-utils.js';
 
 async function createRequestHeaders(
   includeContentType: boolean = true,
 ): Promise<{ [string]: string }> {
   const [{ userId: userID, accessToken }, deviceID] = await Promise.all([
     verifyUserLoggedIn(),
     getContentSigningKey(),
   ]);
 
   const authorization = createHTTPAuthorizationHeader({
     userID,
     deviceID,
     accessToken,
   });
 
   return {
     Authorization: authorization,
     ...(includeContentType && { 'Content-Type': 'application/json' }),
   };
 }
 
 type BlobDescriptor = {
   +hash: string,
   +holder: string,
 };
 
-async function uploadBlob(blob: Blob, hash: string): Promise<void> {
+type BlobOperationResult =
+  | {
+      +success: true,
+    }
+  | {
+      +success: false,
+      +reason: 'HASH_IN_USE' | 'OTHER',
+      +status: number,
+      +statusText: string,
+    };
+
+async function uploadBlob(
+  blob: Blob,
+  hash: string,
+): Promise<BlobOperationResult> {
   const formData = new FormData();
   formData.append('blob_hash', hash);
   formData.append('blob_data', blob);
 
   const headers = await createRequestHeaders(false);
   const uploadBlobResponse = await fetch(
     makeBlobServiceEndpointURL(blobService.httpEndpoints.UPLOAD_BLOB),
     {
       method: blobService.httpEndpoints.UPLOAD_BLOB.method,
       body: formData,
       headers,
     },
   );
 
   if (!uploadBlobResponse.ok) {
     const { status, statusText } = uploadBlobResponse;
-    throw new Error(`Payload upload failed with HTTP ${status}: ${statusText}`);
+    const reason = status === 409 ? 'HASH_IN_USE' : 'OTHER';
+    return {
+      success: false,
+      reason,
+      status,
+      statusText,
+    };
   }
+
+  return { success: true };
 }
 
-async function assignHolder(params: BlobDescriptor): Promise<void> {
+async function assignHolder(
+  params: BlobDescriptor,
+): Promise<BlobOperationResult> {
   const { hash, holder } = params;
   const headers = await createRequestHeaders();
   const assignHolderResponse = await fetch(
     makeBlobServiceEndpointURL(blobService.httpEndpoints.ASSIGN_HOLDER),
     {
       method: blobService.httpEndpoints.ASSIGN_HOLDER.method,
       body: JSON.stringify({
         holder,
         blob_hash: hash,
       }),
       headers,
     },
   );
 
   if (!assignHolderResponse.ok) {
     const { status, statusText } = assignHolderResponse;
-    throw new Error(
-      `Holder assignment failed with HTTP ${status}: ${statusText}`,
-    );
+    return { success: false, reason: 'OTHER', status, statusText };
   }
+
+  return { success: true };
 }
 
-async function upload(blob: Blob, params: BlobDescriptor): Promise<void> {
+async function upload(
+  blob: Blob,
+  params: BlobDescriptor,
+): Promise<
+  | {
+      +success: true,
+    }
+  | {
+      +success: false,
+      +assignHolderResult: BlobOperationResult,
+      +uploadBlobResult: BlobOperationResult,
+    },
+> {
   const { hash, holder } = params;
-  try {
-    await Promise.all([assignHolder({ hash, holder }), uploadBlob(blob, hash)]);
-  } catch (e) {
-    throw new Error(
-      `Payload upload failed with: ${
-        getMessageForException(e) ?? 'unknown error'
-      }`,
-    );
+
+  const [holderResult, uploadResult] = await Promise.all([
+    assignHolder({ hash, holder }),
+    uploadBlob(blob, hash),
+  ]);
+  if (holderResult.success && uploadResult.success) {
+    return { success: true };
   }
+  return {
+    success: false,
+    assignHolderResult: holderResult,
+    uploadBlobResult: uploadResult,
+  };
 }
 
 export type BlobDownloadResult =
   | {
       +found: false,
     }
   | {
       +found: true,
       +blob: Blob,
     };
 async function download(hash: string): Promise<BlobDownloadResult> {
   const url = getBlobFetchableURL(hash);
   const headers = await createRequestHeaders();
   const response = await fetch(url, {
     method: blobService.httpEndpoints.GET_BLOB.method,
     headers,
   });
 
   if (!response.ok) {
     return { found: false };
   }
   const blob = await response.blob();
   return { found: true, blob };
 }
 
 async function deleteBlob(params: BlobDescriptor, instant?: boolean) {
   const { hash, holder } = params;
   const endpoint = blobService.httpEndpoints.DELETE_BLOB;
   const url = makeBlobServiceEndpointURL(endpoint);
   const headers = await createRequestHeaders();
   await fetch(url, {
     method: endpoint.method,
     body: JSON.stringify({
       holder,
       blob_hash: hash,
       instant_delete: !!instant,
     }),
     headers,
   });
 }
 
 export { upload, uploadBlob, assignHolder, download, deleteBlob };