Registered but can't call

I have my SIP settings configured right. It says registered but calls won’t come in or go out. It worked fine up until I installed a new PoE switch. Here is the error, any ideas?

[2013-07-19 20:41:05] WARNING[1690]: chan_sip.c:4164 retrans_pkt: Retransmission timeout reached on transmission [email protected]:5060 for seqno 102 (Critical Request) – See
Packet timed out after 31999ms with no response
[2013-07-19 20:41:05] WARNING[1690]: chan_sip.c:4193 retrans_pkt: Hanging up call [email protected]:5060 - no reply to our critical packet (see
[2013-07-19 20:41:07] WARNING[3887][C-0000004e]: channel.c:4810 ast_prod: Prodding channel ‘SIP/101-0000007a’ failed

Is this from Internal extension to extension? If it’s only happened since you installed a new switch I would suspect a network issue. If it’s a managed or smart switch check that there is not a speed or duplex mismatch on the port that the phone or PBX is plugged into.