diff --git a/core/src/main/java/eu/eudat/depositinterface/zenodorepository/service/ZenodoDepositServiceImpl.java b/core/src/main/java/eu/eudat/depositinterface/zenodorepository/service/ZenodoDepositServiceImpl.java
index 756727e..1099919 100644
--- a/core/src/main/java/eu/eudat/depositinterface/zenodorepository/service/ZenodoDepositServiceImpl.java
+++ b/core/src/main/java/eu/eudat/depositinterface/zenodorepository/service/ZenodoDepositServiceImpl.java
@@ -105,7 +105,7 @@ public class ZenodoDepositServiceImpl implements ZenodoDepositService {
                     if (links == null || !links.containsKey(ZENODO_LINKS_BUCKET)) throw new Exception("bucket not found");
                     
                     String addFileUrl = links.get(ZENODO_LINKS_BUCKET) + "/" + pdfEnvelope.getFilename() + "?access_token=" + zenodoToken;
-                    zenodoClient.put().uri(addFileUrl)
+                    zenodoClient.put().uri(addFileUrl).headers(httpHeaders -> httpHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM))
                             .body(BodyInserters
                                     .fromResource(new ByteArrayResource(pdfEnvelope.getFile())))
                             .retrieve().toEntity(Map.class).block();
@@ -119,7 +119,7 @@ public class ZenodoDepositServiceImpl implements ZenodoDepositService {
                         String supportingFilesZipName = dmpDepositModel.getSupportingFilesZip().getFilename();
 
                         addFileUrl = links.get(ZENODO_LINKS_BUCKET) + "/" + supportingFilesZipName + "?access_token=" + zenodoToken;
-                        zenodoClient.put().uri(addFileUrl).body(BodyInserters.fromResource(new ByteArrayResource(supportingFilesZipName.getBytes()))).retrieve().toEntity(Map.class).block();
+                        zenodoClient.put().uri(addFileUrl).headers(httpHeaders -> httpHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM)).body(BodyInserters.fromResource(new ByteArrayResource(supportingFilesZipName.getBytes()))).retrieve().toEntity(Map.class).block();
                     }
 
                     // Third post call to Zenodo to publish the entry and return the DOI.