diff --git a/src/server/server.py b/src/server/server.py
index 1514cd0..e61cd53 100644
--- a/src/server/server.py
+++ b/src/server/server.py
@@ -122,12 +122,12 @@ class Server(threading.Thread):
 
         if block_indices is not None:
             try:
-                start, end = block_indices.split(":")
-                start, end = map(int, map(str.strip, (start, end)))
+                first_block_index, last_block_index = block_indices.split(":")
+                first_block_index, last_block_index = map(int, map(str.strip, (first_block_index, last_block_index)))
             except Exception as e:
-                logger.error(f"Failed to parse --block_indices ({e}), must be start:end (e.g. 0:33)")
+                logger.error(f"Failed to parse --block_indices ({e}), must be start:end (e.g. 0:18)")
                 raise
-            block_indices = range(start, end)
+            block_indices = range(first_block_index, last_block_index)
         else:
             assert num_blocks is not None
             block_indices = range(num_blocks)  # TODO replace with proper load balancing