I have created an index in Atlas Search like that:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "_id": {
        "type": "objectId"
      },
      ...
      "properties": {
        "type": "embeddedDocuments",
        "dynamic": false,
        "fields": {
          ...
          "stringValueAsToken": {
            "type": "token"
          },
          ...
        }
      },
      ...
    }
  }
}

but i get this error on the mongot server –

java.lang.IllegalStateException: should be impossible for sortable string fields to be present in embedded documents
         at com.xgen.mongot.util.Check.stateAssertion(Check.java:168)
         at com.xgen.mongot.index.lucene.document.single.LuceneSearchIndexFieldValueHandler.handleSortableString(LuceneSearchIndexFieldValueHandler.java:493)
         at com.xgen.mongot.index.lucene.document.single.LuceneSearchIndexFieldValueHandler.handleString(LuceneSearchIndexFieldValueHandler.java:425)
         at com.xgen.mongot.index.lucene.document.block.EmbeddedFieldValueHandler.handleString(EmbeddedFieldValueHandler.java:138)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.handleField(BsonDocumentProcessor.java:152)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.handleDocumentField(BsonDocumentProcessor.java:52)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.handleField(BsonDocumentProcessor.java:93)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.handleField(BsonDocumentProcessor.java:76)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.handleDocumentField(BsonDocumentProcessor.java:52)
         at com.xgen.mongot.index.ingestion.BsonDocumentProcessor.process(BsonDocumentProcessor.java:38)
         at com.xgen.mongot.index.lucene.SingleLuceneIndexWriter.handleInsertOrUpdate(SingleLuceneIndexWriter.java:407)
         at com.xgen.mongot.index.lucene.SingleLuceneIndexWriter.updateIndex(SingleLuceneIndexWriter.java:242)
         at com.xgen.mongot.index.lucene.SingleLuceneIndexWriter.updateIndex(SingleLuceneIndexWriter.java:227)
         at com.xgen.mongot.index.MeteredIndexWriter.updateIndex(MeteredIndexWriter.java:20)
         at com.xgen.mongot.replication.mongodb.common.DefaultDocumentIndexer.indexDocumentEvent(DefaultDocumentIndexer.java:49)
         at com.xgen.mongot.replication.mongodb.common.IndexingWorkScheduler$IndexingTask.run(IndexingWorkScheduler.java:239)
         at com.xgen.mongot.util.FutureUtils.lambda$checkedRunAsync$2(FutureUtils.java:108)
         at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
         at io.micrometer.core.instrument.internal.TimedRunnable.run(TimedRunnable.java:49)
         at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
         at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
         at java.base/java.lang.Thread.run(Thread.java:829)

The issue is with the type token. why is that exception is thrown and how can i create the stringValueAsToken field to be a token?

Tried to create a field in the index that not exists on the mongoDB document and it was succeeded, but once i entered data to that field the searched index failed.