Having a problem creating an alert for a Prometheus Metric

I am trying to setup an alert on my Grafana instance, and any time I try to test any rule I create, I get this returned:

  "firing": true,
  "state": "pending",
  "conditionEvals": " = true",
  "timeMs": "27.050ms",
  "error": "readObjectStart: expect { or n, but found i, error found in #1 byte of ...|invalid par|..., bigger context ...|invalid parameter \"start\"; cannot parse \"\" to a val|...: ",
  "logs": [
    {
      "message": "Condition[0]: Query",
      "data": {
        "from": 1618861701463,
        "queries": [
          {
            "refId": "A",
            "model": {
              "expr": "internal_server_error_total{instance=\"<URL WAS HERE>\"}",
              "instant": false,
              "interval": "",
              "legendFormat": "",
              "refId": "A"
            },
            "datasource": {
              "id": 4,
              "name": "Prometheus"
            },
            "maxDataPoints": 0,
            "intervalMs": 0
          }
        ],
        "to": 1618862001463
      }
    }
  ]
}```