Just an FYI on a problem I found with two DNS of 1and1 ionos.
The affected DNS are 212.227.123.16 and 212.227.123.17 which both are not responding to *.torproject.org domain or sub domains.
I found this out as my system reverted back to the default DNS after a system crash. I'm now using bind on the local system and all is fine.
Just thought to let all know just in case they are using these DNS.
Paul
137CF322859E400455E457DB920F65FFDD222CDF