修改

Areas/Admin/Controllers/MainServer/ActiveRewardController.cs

@@ -163,7 +163,7 @@ namespace MySystem.Areas.Admin.Controllers
             }
             else
             {
-                var start = Convert.ToDateTime(DateTime.Now.AddMonths(-1).ToString("yyyy-MM-01"));
+                var start = Convert.ToDateTime(DateTime.Now.AddMonths(-1).ToString("yyyy-MM") + "-01");
                 var check = db.ActiveReward.Any(m => m.ActDate >= start && m.BrandId == Convert.ToInt32(BrandId));
                 if (check)
                 {