I have OpenWrt 19.07.2 installed on Linksys WRT1900ACS. Periodically (mostly randomly, once in few days or more often) it loses internet (WAN) connection for all devices, wireless and wired. Based on the logs, that happens after or around this event: "netifd: wan (3898): udhcpc: sending renew to (ip address)"
Rebooting the router or restarting WAN interface restores the connection.
Any ideas on how to resolve this issue?