I started to get "Hmm. We’re having trouble finding that site"

[process]

I did setup wireguard on a specific vlan using this https://forum.opnsense.org/index.php?topic=21205.0 (https://docs.opnsense.org/manual/how-tos/wireguard-selective-routing.html)

After that I started to get this "error" in the browser (using firefox). First it wait/spinns for a while and then this message. If I refresh the page it works instantly.
------------------------------------------------------------------------
Hmm. We're having trouble finding that site.

We can't connect to the server at www.dummy.com. Did you mean to go to www.dummy.com?

If you entered the right address, you can:

• Try again later
• Check your network connection
• Check that Firefox has permission to access the web (you might be connected but behind a firewall)

------------------------------------------------------------------------