
Well I too have been a 1and1 customer for nearly 10 years and something very very very bad is happening. Since the Ionos takeover they are running many Nameservers and in the case of one of our domains we have 100's of visitors being bounced to a holding site.
Having spent a month trying to speak to them about this and being given the usual "fob off" that it is a Caching issue etc etc it appears that their Name Servers are failing and they are hiding this from their customers. There simply isn't anything you can do other than lose visitors and set up a website elsewhere "THAT CAME FROM THEM"
We asked if we could simply move our site to a AWS Name Server and that's not possible as we have MyWebsiteBuilder.
You can find out if this is happening to you by checking your website logs as they will just tell you a pack of lies.
The conclusion is this you will lose a huge % of site visitors that you don't know about unless your visitors tell you, when they do Ionos will fob you off with "old broswers" or "Caching" issues and that appears to be a blatant and corporate lie.
This one will not be solved as they have NO WAY to rectify it and we are quite lucky that our brand is involved in AI tech so they saw right through it. 99% of people wont question it but we did and we got the truth, Failing Name Servers and no way to Sort It"
Personally I am engaging solicitors as they have damaged one of our start up brands out of all recognition.