I found what was causing the trouble: Support for network manager 0.9 (which is used in Wheezy) was added in Gajim 0.15.2, but the Wheezy package is 0.15.1.
I tried 0.15.3 from experimental and reconnect is working with this. But 0.15.3 has other bugs: it does not connect to my Prosody server. It causes the following error: Traceback (most recent call last): File "/usr/share/gajim/src/common/xmpp/idlequeue.py", line 533, in _process_events return IdleQueue._process_events(self, fd, flags) File "/usr/share/gajim/src/common/xmpp/idlequeue.py", line 394, in _process_events obj.pollin() File "/usr/share/gajim/src/common/xmpp/transports_nb.py", line 420, in pollin self._do_receive() File "/usr/share/gajim/src/common/xmpp/transports_nb.py", line 606, in _do_receive self._on_receive(received) File "/usr/share/gajim/src/common/xmpp/transports_nb.py", line 620, in _on_receive self.on_receive(data) File "/usr/share/gajim/src/common/xmpp/client_nb.py", line 320, in <lambda> self.onreceive(lambda _data:self._xmpp_connect_machine(mode, _data)) File "/usr/share/gajim/src/common/xmpp/client_nb.py", line 355, in _xmpp_connect_machine self._xmpp_connect_machine(mode='STREAM_STARTED') File "/usr/share/gajim/src/common/xmpp/client_nb.py", line 378, in _xmpp_connect_machine self._on_stream_start() File "/usr/share/gajim/src/common/xmpp/client_nb.py", line 394, in _on_stream_start self._on_connect() File "/usr/share/gajim/src/common/xmpp/client_nb.py", line 451, in _on_connect self.on_connect(self, self.connected) File "/usr/share/gajim/src/common/connection.py", line 1287, in _connect_success return self.connection_accepted(con, con_type) File "/usr/share/gajim/src/common/connection.py", line 1349, in connection_accepted con.Connection.ssl_fingerprint_sha1[-1]) IndexError: list index out of range -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org