My app key for Python does not work any more, and when I try to generate a new key using the app key generator in Eikon I get a Server error, saying that an application with the same name or ID may already exist, regardless of what name I try for the key.
Is the name you are trying to assign to yourself fairly common? It looks like this app name is already assigned to someone else.
Have you tried a name that is more distinct, such as NikosApp1? Please try something unlikely to be assigned, and let us know if this succeeds for you?