I faced with this error during trying to create second instance I hit below errors:
After investigate issue I have been found below explanation from this link
From link:
4.2 Oracle Database XE Installation and Execution Restrictions
Oracle Database XE restricts itself to only one installation per logical environment. The logical environment can either be a virtual host such as a VM or container, or a physical host. If more than one Oracle Database XE installation is attempted to be started in such a logical environment, an “ORA-00442: Oracle Database Express Edition (XE) single instance violation error” is raised and the database will not start. This does not affect any existing installation or new installations of Oracle Database 18c Personal Edition, Oracle Database 18c Standard Edition 2, or Oracle Database 18c Enterprise Edition. To run more than one Oracle Database instance or install more than one copy of the database software, upgrade to Oracle Database 18c Personal Edition, Oracle Database 18c Standard Edition 2, or Oracle Database 18c Enterprise Edition.
As you can see from note You need to use other DB options for can use Second instance in XE version. But while I am searching this error I found Markus Flechtner’s blog
Please review his blog to can see how you can add second instance in XE version.