diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index b042baf..81bda76 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -1764,12 +1764,22 @@
 }
 
 /* VLR informs us that the subscriber has been associated with a conn */
-static void msc_vlr_subscr_assoc(void *msc_conn_ref,
+static int msc_vlr_subscr_assoc(void *msc_conn_ref,
 				 struct vlr_subscr *vsub)
 {
 	struct ran_conn *conn = msc_conn_ref;
 	OSMO_ASSERT(vsub);
-	OSMO_ASSERT(!conn->vsub);
+	if (conn->vsub) {
+		if (conn->vsub == vsub)
+			LOGPCONN(conn, LOGL_NOTICE, "msc_vlr_subscr_assoc(): conn already associated with %s\n",
+				 vlr_subscr_name(vsub));
+		else {
+			LOGPCONN(conn, LOGL_ERROR, "msc_vlr_subscr_assoc(): conn already associated with a subscriber,"
+				 " cannot associate with %s\n", vlr_subscr_name(vsub));
+			return -EINVAL;
+		}
+	}
+
 	conn->vsub = vlr_subscr_get(vsub);
 	OSMO_ASSERT(conn->vsub);
 	conn->vsub->cs.attached_via_ran = conn->via_ran;
@@ -1778,6 +1788,7 @@
 	 * associated with the conn: merge the new Classmark into vsub->classmark. Don't overwrite valid
 	 * vsub->classmark with unset classmark, though. */
 	update_classmark(&conn->temporary_classmark, &conn->vsub->classmark);
+	return 0;
 }
 
 static int msc_vlr_route_gsup_msg(struct vlr_subscr *vsub,
diff --git a/src/libvlr/vlr_access_req_fsm.c b/src/libvlr/vlr_access_req_fsm.c
index 3a0760d..3b40285 100644
--- a/src/libvlr/vlr_access_req_fsm.c
+++ b/src/libvlr/vlr_access_req_fsm.c
@@ -72,7 +72,7 @@
 	bool implicitly_accepted_parq_by_ciphering_cmd;
 };
 
-static void assoc_par_with_subscr(struct osmo_fsm_inst *fi, struct vlr_subscr *vsub)
+static int assoc_par_with_subscr(struct osmo_fsm_inst *fi, struct vlr_subscr *vsub)
 {
 	struct proc_arq_priv *par = fi->priv;
 	struct vlr_instance *vlr = par->vlr;
@@ -81,7 +81,7 @@
 	par->vsub = vsub;
 	/* Tell MSC to associate this subscriber with the given
 	 * connection */
-	vlr->ops.subscr_assoc(par->msc_conn_ref, par->vsub);
+	return vlr->ops.subscr_assoc(par->msc_conn_ref, par->vsub);
 }
 
 static const char *vlr_proc_arq_result_name(const struct osmo_fsm_inst *fi)
@@ -371,8 +371,10 @@
 					  GSM48_REJECT_NETWORK_FAILURE);
 		}
 		vsub->proc_arq_fsm = fi;
-		assoc_par_with_subscr(fi, vsub);
-		proc_arq_vlr_fn_post_imsi(fi);
+		if (assoc_par_with_subscr(fi, vsub) != 0)
+			proc_arq_fsm_done(fi, GSM48_REJECT_NETWORK_FAILURE);
+		else
+			proc_arq_vlr_fn_post_imsi(fi);
 		vlr_subscr_put(vsub);
 		return;
 	}
@@ -414,8 +416,10 @@
 		proc_arq_fsm_done(fi, GSM48_REJECT_IMSI_UNKNOWN_IN_VLR);
 		return;
 	}
-	assoc_par_with_subscr(fi, vsub);
-	proc_arq_vlr_fn_post_imsi(fi);
+	if (assoc_par_with_subscr(fi, vsub))
+		proc_arq_fsm_done(fi, GSM48_REJECT_NETWORK_FAILURE);
+	else
+		proc_arq_vlr_fn_post_imsi(fi);
 	vlr_subscr_put(vsub);
 }
 
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index e635305..b00f8ce 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -954,7 +954,8 @@
 	lfp->vsub = vsub;
 	/* Tell MSC to associate this subscriber with the given
 	 * connection */
-	vlr->ops.subscr_assoc(lfp->msc_conn_ref, lfp->vsub);
+	if (vlr->ops.subscr_assoc(lfp->msc_conn_ref, lfp->vsub))
+		lu_fsm_failure(fi, GSM48_REJECT_NETWORK_FAILURE);
 	return 0;
 }