It's really weird but true that you must set Oracle Apex admin password twice. One time is during Oracle Apex installation, another time where you must reset admin password on start running Oracle Apex for the first time on the browser.
You will need to follow & apply the next steps just in case of:
- Oracle Apex installation.
- You forget Oracle Apex admin password.
- Your Oracle Apex user is locked or blocked.
- Open the cmd command prompt
- Change its prompt path as shown in the following screenshot.
- Then, type SQLPLUS to connect to sys user.
- Run script @apxconf.sql as in the screen shot.
- Use ADMIN by default, or use your Admin user predefined.
- Specify your email or skip this step.
- Specify a strong admin password.