Hi Alexandre, the 404 error =means the URL is wrong in some form when specifying it in the client "http://localhost:9910/magic".
It can specifically be reproduced if the domain is valid (points to some legitimate server, not necessarily MPS), but the requested sub-url is wrong.
Say the correct URL for MPS server component is:
http://localhost:9910/magic
Then you'll get the 404 error if it's something like:
http://localhost/magic http://www.google.com/magic http://localhost:9910/magic01
Notice that localhost (which defaults to localhost:80), localhost:9910 and www.google.com are all valid domains, but the sub-url associated with them is not. There is no "/magic" for either localhost:80 or www.google.com. And there is no "/magic01" for localhost:9910.
Your best bet then is to investigate the MPS URL and check whether it changed ports or whether someone changed its URL somehow (say, by moving the MPS installation to another machine). You can configure the port number in the server with the mps_server_root/config/main_config file.