Redirect URL to another domain with same path in Ghost CMS redirects.json

I try to use Redirect.json for redirect URLs in ghost CMS. I use this in redirect.json file

        "from": "/([a-zA-Z\d.-]+)",
        "to": "$1",
        "permanent": true

its redirect to another domain but in URL its printing $1 its unable to fetch URL path please help me to solve this

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