There are several reasons, the most important one is that my old domain got some big hit and “Negative” Backlinks over the many past years. The old Domain solariz.de was registered more then 20 Years ago, in this Time I did a lot of changes on the Domain, CMS, files I hosted and so on. Those gave me a lot of different Backlinks from all over the World – you might think Backlinks are a great thing.
Yes and no, most of those backlinks are from pages embedding old WordPress or Joomla Plugins I wrote about 15 years ago. They are unsafe, totally open to the wild and partly spreading Malware. One thing of this Backlinks is that I noticed the impact on them on any of my search ratings for my page. But more important than that, I have thousand visiting bots on the page every day. In Addition to the bots there are a lot of embedded scripts loading resources from this old domain. So the webserver currently have alot of traffic I do not want.
Second thing is I want to try a controlled 301 redirect from the old domain to the new. So just to keep the pages I would like to have in the google index and others I do not return a HTTP 1.1 / 301 Redirect instead they give a 404 already on the old domain.
Third one, the new Domain is just nice ????