diff --git a/Lib/nntplib.py b/Lib/nntplib.py
index bf66734..6b0150d 100644
--- a/Lib/nntplib.py
+++ b/Lib/nntplib.py
@@ -364,7 +364,7 @@
             self.nntp_implementation = None
             try:
                 resp, caps = self.capabilities()
-            except NNTPPermanentError:
+            except (NNTPPermanentError, NNTPTemporaryError):
                 # Server doesn't support capabilities
                 self._caps = {}
             else:
@@ -941,6 +941,9 @@
                 resp = self._shortcmd('authinfo pass ' + password)
                 if not resp.startswith('281'):
                     raise NNTPPermanentError(resp)
+        # Capabilities might have changed after login
+        self._caps = None
+        self.getcapabilities()
         # Attempt to send mode reader if it was requested after login.
         if self.readermode_afterauth:
             self._setreadermode()