when using exportable env variables make sure secrets.toml is empty
Example setting up:
export SOURCES__MONGODB__CONNECTION_URL="mongodb://dbuser:passwd@host.or.ip:27017"
export DESTINATION__POSTGRES__CREDENTIALS="postgresql://username:password@host:port/database" DB name for both DESTINATION__POSTGRES__CREDENTIALS="postgresql://username:password@host:port/database" and DBT_DB credential should be the same
