Elasticsearch does not find the result in the first search after the space character in NEST

I am indexing in elasticsearch as I share below. But after I do the indexing process, when I search in autocomplete, it finds the text I searched for before the space, but the first key I press after the space character does not perform the search operation. When I type the 2nd or 3rd character, it returns results. How can I do the search operation with the first character I press after the space character?

The code I added my data to elasticsearch to index.

var createIndexDescriptor = new CreateIndexDescriptor(INDEX_NAME).Mappings(ms => ms.Map<GlobalCompany>(m => m.AutoMap()
                  
                    .Properties(pprops => pprops
                        .Text(ps => ps
                            .Name("Title")
                            .Analyzer("whitespace")
                            .Fielddata(true)
                            .Fields(f => f
                                .Keyword(k => k
                                    .Name("keyword")
                                )
                            )
                        )
                    )
        ));

The code I searched from the data I indexed in elasticsearch.

var searchResponse = eClient.Search<GlobalCompany>(s => s.Index(INDEX_NAME)
                  .Query(q => q
                  .MultiMatch(m => m
                            .Fields(f => f
                             .Field(u => u.Title)
                             .Field(u => u.RegisterNumber))
                            .Type(TextQueryType.PhrasePrefix)
                          .Query(value))));