diff --git a/drivers/modem/gsm_ppp.c b/drivers/modem/gsm_ppp.c
index 3f08f1218c4..9341575414b 100644
--- a/drivers/modem/gsm_ppp.c
+++ b/drivers/modem/gsm_ppp.c
@@ -883,13 +883,13 @@ static void mux_setup(struct k_work *work)
 			}
 		}
 
-		gsm->state = STATE_PPP_CHANNEL;
-
 		ret = mux_attach(gsm->control_dev, uart, DLCI_CONTROL, gsm);
 		if (ret < 0) {
 			goto fail;
 		}
 
+		gsm->state = STATE_PPP_CHANNEL;
+
 		break;
 
 	case STATE_PPP_CHANNEL:
@@ -902,13 +902,13 @@ static void mux_setup(struct k_work *work)
 			}
 		}
 
-		gsm->state = STATE_AT_CHANNEL;
-
 		ret = mux_attach(gsm->ppp_dev, uart, DLCI_PPP, gsm);
 		if (ret < 0) {
 			goto fail;
 		}
 
+		gsm->state = STATE_AT_CHANNEL;
+
 		break;
 
 	case STATE_AT_CHANNEL:
@@ -921,13 +921,13 @@ static void mux_setup(struct k_work *work)
 			}
 		}
 
-		gsm->state = STATE_DONE;
-
 		ret = mux_attach(gsm->at_dev, uart, DLCI_AT, gsm);
 		if (ret < 0) {
 			goto fail;
 		}
 
+		gsm->state = STATE_DONE;
+
 		break;
 
 	case STATE_DONE: