How to set up monolog in symfony to send emails?

Question

symfony

Good day everyone, there is such a problem, I'm setting up logging according to off-line documentation from the symphony website. I write the settings in the config and put throw new Exception () in the action, in theory the page catches a 500 error and a letter with a critical error should come, but nothing comes. If there are methods in the project that send mail and they work fine, what could be the problem? Tried both in dev and prod modes. The logs are written to the file like normal.

monolog:
    handlers:
        main:
            type:         fingers_crossed
            action_level: critical
            handler:      grouped
        grouped:
            type:    group
            members: [streamed, deduplicated]
        streamed:
            type:  stream
            path:  '%kernel.logs_dir%/%kernel.environment%.log'
            level: debug
        deduplicated:
            type:    deduplication
            handler: swift
        swift:
            type:         swift_mailer
            from_email:   'email_from'
            to_email:     'email_to'
            subject:      'An Error Occurred! %%message%%'
            level:        debug
            formatter:    monolog.formatter.html
            content_type: text/html