Multi-Wan and DNS issues!

Good morning, ladies and gentlemen,

I am facing a problem that began after the 21/09 updates. The Multi-wan system has blocked the Internet use after a primary link failure. Having to be removed because it did not return to the main link, even when we restart the system. However after that, even with only 1 link the System needs to be restarted every 30min on average, because the internet stops working and the browsers present a DNS error message