Can't generate changelog from sap ase15.7 database

I am new here and begin to use liquibase to migrate my database from sap ase 15.7 to postgres, however i am getting the above error when trying to genrate changelog.
command: liquibase generate-changelog --log-level=debug --changelog-file=dbchangelog_1.sybase.xml
Error:
ERROR: Exception Primary Class: UnexpectedLiquibaseException
ERROR: Exception Primary Reason: Unknown boolean value: N
ERROR: Exception Primary Source: 4.27.0

Thanks in advance for your help !