Oracle APEX the server requires a username and password the server says XDB

This article from  Mohammad Fawzy

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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.