为什么升级14.5之后隐私跟踪功能无法打开

In some circumstances, the “Allow Apps to Request to Track” setting is disabled, including: 

• For users with child accounts or under age 18 by birth year, signed in with their Apple ID*
• If your Apple ID is managed by an educational institution or uses a configuration profile that limits tracking
• If your Apple ID was created in the last 3 days

In these cases, all apps that request to track are denied permission by default and do not receive the IDFA. If the status of your account or device changes, and you subsequently choose to enable “Allow Apps to Ask to Track,” then the app's next request to track will display the permission prompt to you.

在某些情况下无法使用。大概意思创建三天的ID，18岁的ID，教育机构管理的苹果ID，均无法使用

还有就是看看你是否安装了第三方软件证书 删除它，注销iCloud账号 从新登陆一次也可以解决

还有请看这篇文档：https://support.apple.com/zh-cn/HT211970

说明了开发者如果没有更新隐私政策 目前就无法使用允许跟踪。