diff --git a/state/indexer/block/null/null.go b/state/indexer/block/null/null.go
index 7cc536ed6..d36d8680e 100644
--- a/state/indexer/block/null/null.go
+++ b/state/indexer/block/null/null.go
@@ -2,6 +2,7 @@ package null
 
 import (
 	"context"
+	"errors"
 
 	"github.com/tendermint/tendermint/libs/pubsub/query"
 	"github.com/tendermint/tendermint/state/indexer"
@@ -14,7 +15,7 @@ var _ indexer.BlockIndexer = (*BlockerIndexer)(nil)
 type BlockerIndexer struct{}
 
 func (idx *BlockerIndexer) Has(height int64) (bool, error) {
-	return false, nil
+	return false, errors.New(`indexing is disabled (set 'tx_index = "kv"' in config)`)
 }
 
 func (idx *BlockerIndexer) Index(types.EventDataNewBlockHeader) error {
@@ -22,5 +23,5 @@ func (idx *BlockerIndexer) Index(types.EventDataNewBlockHeader) error {
 }
 
 func (idx *BlockerIndexer) Search(ctx context.Context, q *query.Query) ([]int64, error) {
-	return nil, nil
+	return []int64{}, nil
 }
diff --git a/state/txindex/indexer_service.go b/state/txindex/indexer_service.go
index d7192c8fa..e72601252 100644
--- a/state/txindex/indexer_service.go
+++ b/state/txindex/indexer_service.go
@@ -79,7 +79,7 @@ func (is *IndexerService) OnStart() error {
 			if err := is.blockIdxr.Index(eventDataHeader); err != nil {
 				is.Logger.Error("failed to index block", "height", height, "err", err)
 			} else {
-				is.Logger.Error("indexed block", "height", height, "err", err)
+				is.Logger.Error("indexed block", "height", height)
 			}
 
 			if err = is.txIdxr.AddBatch(batch); err != nil {