@JonFo
That will not work for long, as once the "root" info about openwrt.org gets stale at opendns, that opendns server needs to get new validation from the openwrt.org root DNS server, which is now down.
@jow posted a temporary workaround in Global openwrt.org DNS outage - #3 by jow
You can direct your own DNS client/server (your Openwrt router) to believe that 173.245.58.51 has the correct DNS root info for the whole openwrt.org domain. Jow has configured that with the needed info about the domain.
I did that and all other services work now for me except forum.openwrt.org that is apparently in the same physical server complex as the main DNS server.