Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 245667)
+++ channels/chan_sip.c	(working copy)
@@ -17032,6 +17032,7 @@
 		break;
 	case 415: /* Unsupported media type */
 	case 488: /* Not acceptable here */
+	case 606: /* Not Acceptable */
 		xmitres = transmit_request(p, SIP_ACK, seqno, XMIT_UNRELIABLE, FALSE);
 		if (p->udptl && p->t38.state == T38_LOCAL_REINVITE) {
 			change_t38_state(p, T38_DISABLED);
@@ -17725,6 +17726,7 @@
 			break;
 		case 415: /* Unsupported media type */
 		case 488: /* Not acceptable here - codec error */
+		case 606: /* Not Acceptable */
 			if (sipmethod == SIP_INVITE)
 				handle_response_invite(p, resp, rest, req, seqno);
 			break;