SyncGateway cannot create indexes

I am also getting same error.

2020-07-22T14:41:31.031+05:30 [ERR] cbgt index creation failed: manager_api: could not create index, indexDefs.ImplVersion: “NS41LjA=” > mgr.version: 5.5.0 – base.(*CbgtContext).StartManager() at dcp_sharded.go:304
2020-07-22T14:41:31.031+05:30 [ERR] Error opening database db: manager_api: could not create index, indexDefs.ImplVersion: “NS41LjA=” > mgr.version: 5.5.0 – rest.RunServer() at config.go:1028

We have created channels with smaller number of documents based on document property “TYPE”.

“sync”: function (doc, oldDoc) { channel(doc.TYPE ); }

It is creating channels with name as doc.TYPE. However after making these changes, when we restart Couchbase sync gateway we get different and incorrect counts of document in configured channels every time. We are getting this issue even when channel size is very small and have less than 15 documents. For example we have 12 docs as TYPE TestType however we are getting only 3 documents in TestType channel.
We have created the Couchbase server with 1 node by using cbtransfer command.
We are using windows 10, 16 GB ram and i5 processor. We are using couchbase-server-enterprise_6.5.1 and couchbase-sync-gateway-enterprise_2.7.3_x86_64 for this development.

PFB the updated sync config code.

{
“adminInterface”: “:4985”,
“interface”: “0.0.0.0:4984”,
“log”: [" "],
“databases”: {
“db”: {

“bucket”: “myBucket”,
“username”: “UserName”,
“password”: “**************”,
“enable_shared_bucket_access”: true,
“import_docs”: true,
“num_index_replicas”: 0,
“users”: {
“GUEST”: { “disabled”: false, “admin_channels”: ["
"] }
},
“sync”: `function (doc, oldDoc) {
channel(doc.TYPE );

  }`
}

}