Elastic Search query with "+" prefix character escape not working

I have this issue currently with my elastic search not working suddenly. trying either of the following shows no hits when they are escaped.

GET /policies/_search
{
  "query" : {
    "simple_query_string" : {
      "query" : "\\+4912345678*"
    }
  }
}

GET /policies/_search
{
  "query" : {
    "query_string" : {
      "query" : "\\+4912345678*"
    }
  }
}
{
  "took" : 151,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 0,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  }
}

removing the + plus sign or the escaped character however shows theres a result.