# Debug Note - macOS run apt-get failed in docker

I got an issue while I tried to use docker to build a PHP image. But it failed and the terminal showed the error log below.

![截圖 2022-02-23 13.12.03.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1645593126624/jwSoBDGRu.png)

While I saw the error, the first thought in my mind was network might be blocked by anti-virus software or firewall. Then I checked the setting, it was normal. Then I found this issue [comment](https://github.com/debuerreotype/docker-debian-artifacts/issues/66#issuecomment-476616579).
But it was still not working. However, it seemed an issue about the `source.list`.

I found the `security.debian.org` in `source.list`  was different from others. It was a `http://` and other domains were `https://`. So I change the `security.debian.org` to `https://`. It worked! But why?

I could understand why I need to connect via `https`. I keep researching. Therefore I found the answer from this [comment](https://github.com/docker/for-mac/issues/6030#issuecomment-992590521).

The answer is -- macOS new feature iCloud Private Relay caused this issue. 

Three small. Nice mac.  
This is the journey I solve this issue.