PROBLEM SOLVED !!
Thanks to everyone here and with PM that support me

Finally it was a combination of bad luck and my "expert" knowledge with PC`s...
1) Bad luck that my modem had a fault and interupt or loose connections with "no logic". After I got a new modem and contact the internet supporter the connection was stable.
2) Next thing is that I couldn't get the "IP Control" app from Meridian as my "apple-id" was denied for some reason and the "IP Control" app is in the category "music" and start allways iTunes where my "apple-id" problem get doubled...
3) Then the "IP-control" app is not in the Austrian store, you have to change the store to Germany for example, but then the login to the apple-id get logged out. But the real reason was here that my iPad did not have the newest software. After doing that, I installed the IP-app, and the app found the address but couldn't make a connection.
4) Calling the internet supporter again as my new modem has three adresses instead of one and only could get acces with a 192... number instead of 10.0 the real expert correct that and give also the 218 a 10... number so I got finally access and the app is working.!!
5) That "accident" happened when I opened the 218 via the webbrowser on the first evening and just when I try to store my setup and changed the 218 to a permanent address for "stability" the data get stored (from the router) and got the 192.. address - thats about that was the expert told me.
6) After I updated the iPad to version 11.01... the Meridian "core control" don't work anymore. Maybe other apps also have problems, I am not in a mood now to test that all.
But, what is most important is that I can listen to music now as also my 800 is dead,
where I also "played" a part of that.
Rick, I will and can try out now to check my ID40 again, maybe it isn't broken and it was a similar problem with the 218.
Once again, a big THANK to everybody