我已经根据谷歌文档建议https://developers.google.com/search/docs/advanced/crawling/localized-versions?hl=en&visit_id=637562504603988897-547389416&rd=2创建了带有 hreflang 的链接标签以添加到我的网站并添加在我的应用程序的头部，但我试图在谷歌抓取它之前检查我所有的 hreflang 标签是否正确，为此，我正在检查https://technicalseo.com/tools/hreflang/，它返回缺少的返回链接。
这些是我创建的标签：
<link rel="alternate" hreflang="x-default" href="https://031723e32744.ngrok.io/" />
<link rel="alternate" hreflang="en" href="https://031723e32744.ngrok.io/en/" />
<link rel="alternate" hreflang="pt" href="https://031723e32744.ngrok.io/pt/" />
<link rel="alternate" hreflang="es" href="https://031723e32744.ngrok.io/es/" />
<link rel="alternate" hreflang="it" href="https://031723e32744.ngrok.io/it/" />
<link rel="alternate" hreflang="de" href="https://031723e32744.ngrok.io/de/" />
<link rel="alternate" hreflang="zh" href="https://031723e32744.ngrok.io/zh/" />
<link rel="alternate" hreflang="sv" href="https://031723e32744.ngrok.io/sv/" />
<link rel="alternate" hreflang="fr" href="https://031723e32744.ngrok.io/fr/" />
<link rel="alternate" hreflang="nl" href="https://031723e32744.ngrok.io/nl/" />
<link rel="alternate" hreflang="ru" href="https://031723e32744.ngrok.io/ru/" />
<link rel="alternate" hreflang="vi" href="https://031723e32744.ngrok.io/vi/" />
<link rel="alternate" hreflang="tr" href="https://031723e32744.ngrok.io/tr/" />
<link rel="alternate" hreflang="hi" href="https://031723e32744.ngrok.io/hi/" />
<link rel="alternate" hreflang="ko" href="https://031723e32744.ngrok.io/ko/" />
<link rel="alternate" hreflang="ja" href="https://031723e32744.ngrok.io/ja/" />
<link rel="alternate" hreflang="ar" href="https://031723e32744.ngrok.io/ar/" />
<link rel="alternate" hreflang="id" href="https://031723e32744.ngrok.io/id/" />
<link rel="alternate" hreflang="bn" href="https://031723e32744.ngrok.io/bn/" />
<link rel="alternate" hreflang="da" href="https://031723e32744.ngrok.io/da/" />
<link rel="alternate" hreflang="fa" href="https://031723e32744.ngrok.io/fa/" />
<link rel="alternate" hreflang="gu" href="https://031723e32744.ngrok.io/gu/" />
<link rel="alternate" hreflang="jv" href="https://031723e32744.ngrok.io/jv/" />
<link rel="alternate" hreflang="mr" href="https://031723e32744.ngrok.io/mr/" />
<link rel="alternate" hreflang="ms" href="https://031723e32744.ngrok.io/ms/" />
<link rel="alternate" hreflang="no" href="https://031723e32744.ngrok.io/no/" />
<link rel="alternate" hreflang="pa" href="https://031723e32744.ngrok.io/pa/" />
<link rel="alternate" hreflang="pl" href="https://031723e32744.ngrok.io/pl/" />
<link rel="alternate" hreflang="ta" href="https://031723e32744.ngrok.io/ta/" />
<link rel="alternate" hreflang="te" href="https://031723e32744.ngrok.io/te/" />
<link rel="alternate" hreflang="th" href="https://031723e32744.ngrok.io/th/" />
<link rel="alternate" hreflang="tl" href="https://031723e32744.ngrok.io/tl/" />
<link rel="alternate" hreflang="ur" href="https://031723e32744.ngrok.io/ur/" />
<link rel="alternate" hreflang="el" href="https://031723e32744.ngrok.io/el/" />
<link rel="alternate" hreflang="he" href="https://031723e32744.ngrok.io/he/" />
<link rel="alternate" hreflang="hu" href="https://031723e32744.ngrok.io/hu/" />
<link rel="alternate" hreflang="ro" href="https://031723e32744.ngrok.io/ro/" />
<link rel="alternate" hreflang="sk" href="https://031723e32744.ngrok.io/sk/" />
任何人都可以为这个问题提出一个解决方案吗？