diff --git a/src/mod/endpoints/mod_verto/mod_verto.c b/src/mod/endpoints/mod_verto/mod_verto.c
index fe80c0d4b0..7e91371f0d 100644
--- a/src/mod/endpoints/mod_verto/mod_verto.c
+++ b/src/mod/endpoints/mod_verto/mod_verto.c
@@ -1539,7 +1539,7 @@ new_req:
 			len = request.content_length - bytes;
 
 			if ((len = ws_raw_read(&jsock->ws, buffer + bytes, len, jsock->ws.block)) < 0) {
-				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Read error %d\n", len);
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Read error %" SWITCH_SIZE_T_FMT"\n", len);
 				goto done;
 			}