Netplan configurations stop working after some time

Question

I have this Ubuntu Server 18.04 LTS running and recently I changed my router subnet to 10.10.1.X. Also, I set DHCP to assign from 10.10.1.105 - 10.10.1.253 to other devices, since I want 100,101,102 and 103 for static purposes.

So, since in Ubuntu 18.04 netplan is now used, I have it set accordingly:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s20:
      dhcp4: no
      dhcp6: no
      addresses: [10.10.1.100/24]
      gateway4: 10.10.1.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4]

I generate the configurations and run apply and it works for a while. Then, it stops probing websites: I can still use it on lan, but can no longer curl or nslookup. However, my Plex Server always works, since it accepts external connections.

After apply, netstat -r shows the correct routes but when it stops probing, they all disappear!

Edit: I have also disabled IPV6 a while ago, to implement a kill switch. But the kill switch is off right now

Edit 2: Just reset everything. Re-enabled IPv6 and used the same configuration file as before but with 8.8.8.8 and 1.1.1.1 as dns servers and removed the dhcp6: no. After rebooting it was working and then stops working

Edit 3: Removing nameservers I get this message

nslookup google.com
Server:     127.0.0.53
Address:    127.0.0.53#53

** server can't find google.com: SERVFAIL

When I readd nameservers, it work for a while, thens stops working, and eventually it works again. Am I being blocked by nameservers??