diff --git a/include/re_sip.h b/include/re_sip.h
index f4fce22..e5524f3 100644
--- a/include/re_sip.h
+++ b/include/re_sip.h
@@ -282,6 +282,7 @@ void sip_reply_addr(struct sa *addr, const struct sip_msg *msg, bool rport);
 int  sip_auth_authenticate(struct sip_auth *auth, const struct sip_msg *msg);
 int  sip_auth_alloc(struct sip_auth **authp, sip_auth_h *authh,
 		    void *arg, bool ref);
+void sip_auth_reset(struct sip_auth *auth);
 
 
 /* dialog */
diff --git a/src/sip/auth.c b/src/sip/auth.c
index d6288ac..30ae464 100644
--- a/src/sip/auth.c
+++ b/src/sip/auth.c
@@ -285,3 +285,12 @@ int sip_auth_alloc(struct sip_auth **authp, sip_auth_h *authh,
 
 	return 0;
 }
+
+
+void sip_auth_reset(struct sip_auth *auth)
+{
+	if (!auth)
+		return;
+
+	list_flush(&auth->realml);
+}
diff --git a/src/sipreg/reg.c b/src/sipreg/reg.c
index 367c128..a108c0e 100644
--- a/src/sipreg/reg.c
+++ b/src/sipreg/reg.c
@@ -168,6 +168,10 @@ static void response_handler(int err, const struct sip_msg *msg, void *arg)
 
 			return;
 
+		case 403:
+			sip_auth_reset(reg->auth);
+			break;
+
 		case 423:
 			minexp = sip_msg_hdr(msg, SIP_HDR_MIN_EXPIRES);
 			if (!minexp || !pl_u32(&minexp->val) || !reg->expires)