I am trying to generate the report from OracleDB --19c with ora2pg --V23.1.
Command Used: ora2pg -t show_report --dump_as_html -l db_report_filename.html -c E:\ora2pg\ora2pg.cong
Error generated in html report:
FATAL: ORA-00604: error occurred at recursive SQL level 1 ORA-08177: can't serialize access for this transaction (DBD ERROR: OCIStmtExecute)
Looking for ideas to resolve this issue.

This issue was fixed when a configuration change in ora2pg conf file was changed
Data are exported in serialized transaction mode to have a consistent snapshot of the data, see Oracle documentation about what parameter to increase to not have this issue. Or if you are sure that no modification are done in the Oracle database you can force Ora2Pg to use a readonly transaction instead, see TRANSACTION directive in ora2pg.conf