Oracle APEX the server requires a username and password the server says XDB
This article from Mohammad Fawzy
The article direct link Oracle APEX the server requires a username and password the server says XDB
Summary
After install APEX on enterprise edition database you will get the following message if you try to connect to APEX “the server requires a username and password the server says XDB”
In a new installation, we must configure the embedded PL/SQL gateway by running the configuration script apex_epg_config.sql. Then, we must unlock the ANONYMOUS account.
OraPedia 