diff --git a/rpyc/utils/server.py b/rpyc/utils/server.py
index 2079ffd6..c7374510 100644
--- a/rpyc/utils/server.py
+++ b/rpyc/utils/server.py
@@ -317,15 +317,8 @@ class ThreadPoolServer(Server):
     def __init__(self, *args, **kwargs):
         '''Initializes a ThreadPoolServer. In particular, instantiate the thread pool.'''
         # get the number of threads in the pool
-        self.nbthreads = 20
-        if 'nbThreads' in kwargs:
-            self.nbthreads = kwargs['nbThreads']
-            del kwargs['nbThreads']
-        # get the request batch size
-        self.request_batch_size = 10
-        if 'requestBatchSize' in kwargs:
-            self.request_batch_size = kwargs['requestBatchSize']
-            del kwargs['requestBatchSize']
+        self.nbthreads = kwargs.pop('nbThreads', 20)
+        self.request_batch_size = kwargs.pop('requestBatchSize', 10)
         # init the parent
         Server.__init__(self, *args, **kwargs)
         # a queue of connections having something to process
@@ -476,11 +469,7 @@ def _authenticate_and_build_connection(self, sock):
         # authenticate
         if self.authenticator:
             h, p = sock.getpeername()
-            try:
-                sock, credentials = self.authenticator(sock)
-            except AuthenticationError:
-                self.logger.warning("%s:%s failed to authenticate, rejecting connection", h, p)
-                return None
+            sock, credentials = self.authenticator(sock)
         else:
             credentials = None
         # build a connection
@@ -496,16 +485,12 @@ def _accept_method(self, sock):
             # authenticate and build connection object
             conn = self._authenticate_and_build_connection(sock)
             # put the connection in the active queue
-            if conn:
-                h, p = sock.getpeername()
-                fd = conn.fileno()
-                self.logger.debug("Created connection to %s:%d with fd %d", h, p, fd)
-                self.fd_to_conn[fd] = conn
-                self._add_inactive_connection(fd)
-                self.clients.clear()
-            else:
-                self.logger.warning("Failed to authenticate and build connection, closing %s:%d", h, p)
-                sock.close()
+            h, p = sock.getpeername()
+            fd = conn.fileno()
+            self.logger.debug("Created connection to %s:%d with fd %d", h, p, fd)
+            self.fd_to_conn[fd] = conn
+            self._add_inactive_connection(fd)
+            self.clients.clear()
         except Exception:
             h, p = sock.getpeername()
             self.logger.exception("Failed to serve client for %s:%d, caught exception", h, p)