Apex 20.1 installed on 18c express edition but failed it in below steps, rest of the steps were successful. I am getting different login screen. PFA. I can't login using different possible methods/users. please assist. Steps followed in following link, https://www.foxinfotech.in/2019/04/install-oracle-apex-19-1-in-eleven-easy-steps.html error : . FAIL - This version of Application Express is already installed. . FAIL - Precondition for Phase 1 failed: APEX_200100 already exists SQL> @apxrtins.sql SYSAUX SYSAUX TEMP /i/ ...set_appun.sql PL/SQL procedure successfully completed. ...set_ufrom_and_upgrade.sql PL/SQL procedure successfully completed. Session altered. FOO3 -------------------------------- installrt2020-10-09_15-19-09.log . ORACLE . . Application Express Runtime Installation. ........................................... . ...set_appun.sql ... Checking prerequisites (RUNTIME) . . SYSDBA Privilege . pass - Connection with SYSDBA privilege. . Database rolling upgrade . pass - No rolling upgrade. . DB components . FAIL - This version of Application Express is already installed. . pass - CATPROC: version=18.0.0.0.0 . pass - XDB: version=18.0.0.0.0 . XDB . pass - skipped (RUNTIME install) . PL/SQL Web Toolkit . pass - version 11.2.0.0.1 . Tablespaces . pass - found SYSAUX . pass - found SYSAUX . pass - found TEMP . PHASES (1,2,3)... . FAIL - Precondition for Phase 1 failed: APEX_200100 already exists . . 2 errors occurred declare * ERROR at line 1: ORA-20001: Prerequisite checks failed; unable to proceed ...