HelloSign signature_request_invalid error due to the text tags

Error Text Tag

{
   "event":{
      "event_type":"signature_request_invalid",
      "event_time":"1512619951",
      "event_hash":"3f4aa4a2cd374fe47a758cff1fd9ff6578fa5ad8e273a174d8d034cb094a85c4",
      "event_metadata":{
         "related_signature_id":null,
         "reported_for_account_id":"bc1225d28a648231a589100c07c9f17c82d80411",
         "reported_for_app_id":null
      }
   },
   "account_guid":"bc1225d28a648231a589100c07c9f17c82d80411",
   "client_id":null,
   "signature_request":{
      "signature_request_id":"c70e0a0a4d0d106200760e803e738e1ee1d92756",
      "test_mode":true,
      "title":"using postman",
      "original_title":"using postman",
      "subject":"using postman",
      "message":"Three Signers multiple pages",
      "metadata":{

      },
      "is_complete":false,
      "is_declined":false,
      "has_error":true,
      "custom_fields":[

      ],
      "response_data":[

      ],
      "signing_url":null,
      "signing_redirect_url":null,
      "files_url":"https:\/\/api.hellosign.com\/v3\/signature_request\/files\/c70e0a0a4d0d106200760e803e738e1ee1d92756",
      "details_url":"https:\/\/app.hellosign.com\/home\/manage?guid=c70e0a0a4d0d106200760e803e738e1ee1d92756",
      "requester_email_address":"alex@hellosign.com",
      "signatures":[
         {
            "signature_id":"06af1d204bdee59f068afe647c447a7bb",
            "has_pin":false,
            "signer_email_address":"testing+doctagerror@hellosign.com",
            "signer_name":"Mr Postman",
            "order":null,
            "status_code":"error_text_tag",
            "signed_at":null,
            "last_viewed_at":null,
            "last_reminded_at":null,
            "error":"Text tags error: Check for correct signers and correct text tag syntax."
         }
      ],
      "cc_email_addresses":[

      ]
   }
}