diff --git a/dvuploader/directupload.py b/dvuploader/directupload.py
index e22c729..18c1607 100644
--- a/dvuploader/directupload.py
+++ b/dvuploader/directupload.py
@@ -6,6 +6,7 @@
 from urllib.parse import urljoin
 import aiofiles
 import aiohttp
+import aiohttp_retry
 
 from dvuploader.file import File
 from dvuploader.nativeupload import file_sender
@@ -13,11 +14,14 @@
 
 TESTING = bool(os.environ.get("DVUPLOADER_TESTING", False))
 MAX_FILE_DISPLAY = int(os.environ.get("DVUPLOADER_MAX_FILE_DISPLAY", 50))
+MAX_RETRIES = int(os.environ.get("DVUPLOADER_MAX_RETRIES", 10))
 
 assert isinstance(
     MAX_FILE_DISPLAY, int
 ), "DVUPLOADER_MAX_FILE_DISPLAY must be an integer"
 
+assert isinstance(MAX_RETRIES, int), "DVUPLOADER_MAX_RETRIES must be an integer"
+
 TICKET_ENDPOINT = "/api/datasets/:persistentId/uploadurls"
 ADD_FILE_ENDPOINT = "/api/datasets/:persistentId/addFiles"
 UPLOAD_ENDPOINT = "/api/datasets/:persistentId/add?persistentId="
@@ -80,24 +84,27 @@ async def direct_upload(
         "x-amz-tagging": "dv-state=temp",
     }
 
-    connector = aiohttp.TCPConnector(limit=4)
+    connector = aiohttp.TCPConnector(limit=10, force_close=True)
     pbar = progress.add_task("╰── [bold white]Registering files", total=len(files))
     results = []
     async with aiohttp.ClientSession(
         headers=headers,
         connector=connector,
     ) as session:
-        for file in files:
-            results.append(
-                await _add_file_to_ds(
-                    session=session,
-                    file=file,
-                    dataverse_url=dataverse_url,
-                    pid=persistent_id,
-                )
+
+        register_tasks = [
+            _add_file_to_ds(
+                session=session,
+                file=file,
+                dataverse_url=dataverse_url,
+                pid=persistent_id,
+                progress=progress,
+                pbar=pbar,
             )
+            for file in files
+        ]
 
-            progress.update(pbar, advance=1)
+        results = await asyncio.gather(*register_tasks)
 
     for file, status in zip(files, results):
         if status is False:
@@ -486,6 +493,8 @@ async def _add_file_to_ds(
     dataverse_url: str,
     pid: str,
     file: File,
+    progress,
+    pbar,
 ) -> bool:
     """
     Adds a file to a Dataverse dataset.
@@ -514,11 +523,23 @@ async def _add_file_to_ds(
         by_alias=True,
         exclude={"to_replace", "file_id"},
         indent=2,
+        exclude_none=True,
     )
 
     with aiohttp.MultipartWriter("form-data") as writer:
         json_part = writer.append(json_data)
         json_part.set_content_disposition("form-data", name="jsonData")
 
-        async with session.post(url, data=writer) as response:
-            return response.status == 200
+        retry_options = aiohttp_retry.RandomRetry(attempts=MAX_RETRIES, statuses={400})
+        retry_client = aiohttp_retry.RetryClient(
+            client_session=session,
+            retry_options=retry_options,
+        )
+
+        async with retry_client.post(url, data=writer) as response:
+            if response.status == 200:
+                progress.update(pbar, advance=1)
+                return True
+
+        await retry_client.close()
+        return False