Failed to deploy Vaultwarden

When I try to deploy Vaultwarden, the following error is returned. How can I resolve this issue?

{
    "code": 500,
    "statusText": "",
    "message": "Ingress.networking.k8s.io \"vaultwarden-zhjuuhnv\" is invalid: [spec.rules[0].host: Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*'), spec.tls[0].hosts[0]: Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')]",
    "data": {
        "apiVersion": "v1",
        "code": 422,
        "details": {
            "causes": [
                {
                    "field": "spec.rules[0].host",
                    "message": "Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')",
                    "reason": "FieldValueInvalid"
                },
                {
                    "field": "spec.tls[0].hosts[0]",
                    "message": "Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')",
                    "reason": "FieldValueInvalid"
                }
            ],
            "group": "networking.k8s.io",
            "kind": "Ingress",
            "name": "vaultwarden-zhjuuhnv"
        },
        "kind": "Status",
        "message": "Ingress.networking.k8s.io \"vaultwarden-zhjuuhnv\" is invalid: [spec.rules[0].host: Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*'), spec.tls[0].hosts[0]: Invalid value: \"vmzpjefc.$(REGION_NAME).$(REGION_USER_DOMAIN)\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')]",
        "metadata": {},
        "reason": "Invalid",
        "status": "Failure"
    }
}