VPN asus RT-AC88U "merlin" not reconnecting after isp diconnect

[Cyberpouet]

Hello,
My VPN not have an automatic reconnect after isp ipchange (or modem deconnect).

ASUS RT-AC88U
firmware 384.2_2
I'm connect with ExpressVPN
TLS Renegotiation time -1
Connection retry attemps -1
Personnal configuration:
"
fast-io
remote-random
pull
tls-client
verify-x509-name Server name-prefix
ns-cert-type server
route-method exe
route-delay 2
tun-mtu 1500
fragment 1300
mssfix 1450
keysize 256
sndbuf 524288
rcvbuf 524288
"
Thanks in advance.