diff --git a/Controllers/SubmissionController.cs b/Controllers/SubmissionController.cs
index da9e610..ed84c5c 100644
--- a/Controllers/SubmissionController.cs
+++ b/Controllers/SubmissionController.cs
@@ -44,7 +44,7 @@ namespace _2021_backend.Controllers
 
             var stu = context.Students.FirstOrDefault(e => e.Stuid == stuid);
             if (stu == null) return Ok(ApiResponse.Error("INVALID_STUID"));
-            else if (DateTime.Now - stu.LastCaptchaTime < TimeSpan.FromMinutes(1)) return Ok(ApiResponse.Error($"ALREADY_SENT,{DateTime.Now.ToString("f")},{stu.LastCaptchaTime.ToString("f")}"));
+            else if (DateTime.Now - stu.LastCaptchaTime < TimeSpan.FromMinutes(1)) return Ok(ApiResponse.Error($"ALREADY_SENT"));
             var result = await TencentSMS.Send(context, SMSType.Captcha, stu, "smsbot");
             if (!result) return Ok(ApiResponse.Error("SEND_ERROR"));
             return Ok(ApiResponse.Success("success"));
diff --git a/Dockerfile b/Dockerfile
index cb74ee3..ee1d227 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -21,4 +21,7 @@ FROM base AS final
 WORKDIR /app
 COPY --from=publish /app/publish .
 
+RUN ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
+RUN echo 'Asia/Shanghai' >/etc/timezone
+
 ENTRYPOINT ["dotnet", "2021-backend.dll"]
\ No newline at end of file