diff --git a/duplicity/backends/dpbxbackend.py b/duplicity/backends/dpbxbackend.py
index d7525b66..4b70e50f 100644
--- a/duplicity/backends/dpbxbackend.py
+++ b/duplicity/backends/dpbxbackend.py
@@ -98,7 +98,14 @@ def __init__(self, parsed_url):
         self.auth_flow = None
 
         self.login()
-
+    def user_authenticated(self):
+        try:
+            account = self.api_client.users_get_current_account()
+            log.Debug("User authenticated as ,%s" % account)
+            return True
+        except:
+            log.Debug('User not authenticated')
+            return False
     def load_access_token(self):
         return os.environ.get('DPBX_ACCESS_TOKEN', None)
 
@@ -196,10 +203,14 @@ def _put(self, source_path, remote_filename):
                                    (res_metadata.size, file_size))
 
     def put_file_small(self, source_path, remote_path):
+        if not self.user_authenticated():
+            self.login()
+
         file_size = os.path.getsize(source_path.name)
         f = source_path.open('rb')
         try:
             log.Debug('dpbx,files_upload(%s, [%d bytes])' % (remote_path, file_size))
+
             res_metadata = self.api_client.files_upload(f, remote_path,
                                                         mode=WriteMode.overwrite,
                                                         autorename=False,
@@ -212,6 +223,9 @@ def put_file_small(self, source_path, remote_path):
             f.close()
 
     def put_file_chunked(self, source_path, remote_path):
+        if not self.user_authenticated():
+            self.login()
+
         file_size = os.path.getsize(source_path.name)
         f = source_path.open('rb')
         try:
@@ -295,6 +309,10 @@ def put_file_chunked(self, source_path, remote_path):
                     log.Debug('dpbx,files_upload_session_append: %s' % e)
 
                     retry_number -= 1
+
+                    if not self.user_authenticated():
+                        self.login()
+
                     if retry_number == 0:
                         raise
 
@@ -320,6 +338,9 @@ def put_file_chunked(self, source_path, remote_path):
 
     @command()
     def _get(self, remote_filename, local_path):
+        if not self.user_authenticated():
+            self.login()
+
         remote_dir = urllib.unquote(self.parsed_url.path.lstrip('/'))
         remote_path = '/' + os.path.join(remote_dir, remote_filename).rstrip()
 
@@ -353,6 +374,8 @@ def _get(self, remote_filename, local_path):
     @command()
     def _list(self):
         # Do a long listing to avoid connection reset
+        if not self.user_authenticated():
+            self.login()
         remote_dir = '/' + urllib.unquote(self.parsed_url.path.lstrip('/')).rstrip()
 
         log.Debug('dpbx.files_list_folder(%s)' % remote_dir)
@@ -373,6 +396,9 @@ def _list(self):
 
     @command()
     def _delete(self, filename):
+        if not self.user_authenticated():
+            self.login()
+
         remote_dir = urllib.unquote(self.parsed_url.path.lstrip('/'))
         remote_path = '/' + os.path.join(remote_dir, filename).rstrip()
 
@@ -390,6 +416,8 @@ def _close(self):
 
     @command()
     def _query(self, filename):
+        if not self.user_authenticated():
+            self.login()
         remote_dir = urllib.unquote(self.parsed_url.path.lstrip('/'))
         remote_path = '/' + os.path.join(remote_dir, filename).rstrip()
 
@@ -399,6 +427,8 @@ def _query(self, filename):
         return {'size': info.size}
 
     def check_renamed_files(self, file_list):
+        if not self.user_authenticated():
+            self.login()
         bad_list = [x for x in file_list if DPBX_AUTORENAMED_FILE_RE.search(x) is not None]
         if len(bad_list) == 0:
             return