[Serusers] ATA 186 : problem with 2 calls at the same time.

Hi, I have a problem with a Cisco ATA 186(code 3.1.0), when i try to make 2 calls at the same time, I have this error on my Gateway CISCO AS5300 for the second call. Thanks in advance. Nicolas RUIZ INVITE sip:0156384166@sip.vivaction.net;user=phone SIP/2.0 Via: SIP/2.0/UDP 62.39.70.245:20048 From: Nicolas RUIZ 2 <sip:0170708662@sip.vivaction.net;user=phone>;tag=3046121938 To: <sip:0156384166@sip.vivaction.net;user=phone> Call-ID: 1497465329(a)62.39.70.245 CSeq: 1 INVITE Contact: Nicolas RUIZ 2 <sip:0170708662@62.39.70.245:20051;user=phone;transport=udp> User-Agent: Cisco ATA 186 v3.1.0 atasip (040211A) Expires: 300 Allow: ACK, BYE, CANCEL, INVITE, NOTIFY, OPTIONS, REFER, REGISTER Content-Length: 227 Content-Type: application/sdp v=0 o=0170708662 36257 36257 IN IP4 62.39.70.245 s=ATA186 Call c=IN IP4 62.39.70.245 t=0 0 m=audio 20060 RTP/AVP 0 8 101 a=rtpmap:0 PCMU/8000/1 a=rtpmap:8 PCMA/8000/1 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 *Sep 13 10:36:27.738: Received ;screen= ;privacy= -> Setting Octet3A=0x80 *Sep 13 10:36:27.738: sipSPIDoAudioNegotiation: Media negotiation failed for m-line 1 *Sep 13 10:36:27.742: sipSPIDoMediaNegotiation: ERROR - no valid fax or audio streams *Sep 13 10:36:27.742: sipSPIHandleInviteMedia: Media Negotiation failed for an incoming call - Sending 488 *Sep 13 10:36:27.742: Queued event from SIP SPI : SIPSPI_EV_SEND_MESSAGE *Sep 13 10:36:27.742: Sent: SIP/2.0 488 Not Acceptable Media Via: SIP/2.0/UDP 62.39.70.245:20048 From: Nicolas RUIZ 2 <sip:0170708662@sip.vivaction.net;user=phone>;tag=3046121938 To: <sip:0156384166@sip.vivaction.net;user=phone>;tag=1C9AE8D8-1E32 Date: Mon, 13 Sep 2004 10:36:27 GMT Call-I as5300-VoIP#D: 1497465329(a)62.39.70.245 Server: Cisco-SIPGateway/IOS-12.x CSeq: 1 INVITE Allow-Events: telephone-event Content-Length: 0 *Sep 13 10:36:27.802: Received: ACK sip:0156384166@sip.vivaction.net;user=phone SIP/2.0 Via: SIP/2.0/UDP 62.39.70.245:20048 From: Nicolas RUIZ 2 <sip:0170708662@sip.vivaction.net;user=phone>;tag=3046121938 To: <sip:0156384166@sip.vivaction.net;user=phone>;tag=1C9AE8D8-1E32 Call-ID: 1497465329(a)62.39.70.245 CSeq: 1 ACK User-Agent: Cisco ATA 186 v3.1.0 atasip (040211A) Content-Length: 0