解決辦法：進入到Fiddler-->Rules-->Customize Rules

在main()方法上方新增

static function DoReattach(o: Object, ea: EventArgs)
 {
    ScheduledTasks.ScheduleWork("reattach", 1000, innerReattach);
 }

 static function innerReattach()
 {
    FiddlerApplication.UI.actAttachProxy();
 }

 static function OnRetire()
 {
    FiddlerApplication.oProxy.remove_DetachedUnexpectedly(DoReattach);
 }
 

在main()方法中新增

FiddlerApplication.oProxy.add_DetachedUnexpectedly(DoReattach);

原文：Reattaching Fiddler automatically is perilous for a bunch of reasons, but yes, it's technically possible to observe changes in the proxy setting for the current user and reattach if they change.

In CustomRules, add the following code:

static function DoReattach(o: Object, ea: EventArgs)
{
   ScheduledTasks.ScheduleWork("reattach", 1000, innerReattach);
}

static function innerReattach()
{
   FiddlerApplication.UI.actAttachProxy();
}

static function OnRetire()
{
   FiddlerApplication.oProxy.remove_DetachedUnexpectedly(DoReattach);
}