One or more schema objects could not be imported during the migration process.
From the error itself it's clear that the schema-name format is not supported in Postgres.
To perform the migration successfully it's recommended to proceed with the offline migration.
When the offline migration script will be generated, one can manually change the schema name like below:
postgres=# CREATE SCHEMA "mantis-mtsn";
Below is the test case which was conducted:
Type "help" for help.
postgres=# CREATE SCHEMA mantis-mtsn
ERROR: syntax error at or near "-"
LINE 1: CREATE SCHEMA mantis-mtsn
List of schemas
Name | Owner
mantis-mtsn | postgres
public | postgres
We see in the above example that thorugh offline migration the schema was successfully migrated from mysql to postgres.