After update to 21.7 no DNS

[lamera]

Hello together  :)

I did the big update to 21.7 today. The update process was fast and after the reboot I had no more name resolution. Under System > Settings > General I wanted to add the lost DNS entries again. But I get the following error:

Code Select Expand

The following input errors were detected:

    You can not assign a gateway to DNS server "8.8.8.8" which is on a directly connected network.

After researching on the web, I got the idea that something must be wrong with the network interfaces.
I have 3 network ports:

• igb0(WAN)
• igb1(LAN)
• igb2(Not used)

Since the update I have a fourth option under interfaces > assignments:

• pppoe0 (igb0) - myusername@domain.com

Before the upgrade this pppoe configuration was integrated in the WAN interface.
What can I do now so that the OPNsense box can resolve domains again?

I tried already:

• reboot
• remove WAN interface and re-add

Thanks for your help!