Prove GitHub: `error: Got reply 504`

I am attempting to prove my GitHub account with the following gist, but I receive the error

```
error: Got reply 504
```

~~gist: https://gist.github.com/jish/9907523~~

**edit:** I deleted that gist, created a new one two days later, and it worked.

The report concerns GitHub account proofing and a `504` reply, but the referenced gist was deleted and the author later succeeded with a new gist. Start by checking whether the failure can still be reproduced; done would require a confirmed cause and a clearly scoped fix or updated reproduction.

Written by the indexing model from the issue text.