Error: "Document.getInitialProps()" should resolve to an object with a "html" prop set with a valid html string

[shenanigansd]

Error occurred prerendering page "/ru/about". Read more: https://nextjs.org/docs/messages/prerender-error
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11:14:31.416 | Error: "Document.getInitialProps()" should resolve to an object with a "html" prop set with a valid html string
11:14:31.419 | at loadDocumentInitialProps (/vercel/path0/node_modules/next/dist/server/render.js:698:23)
11:14:31.419 | at async renderDocument (/vercel/path0/node_modules/next/dist/server/render.js:781:43)
11:14:31.420 | at async renderToHTML (/vercel/path0/node_modules/next/dist/server/render.js:819:28)
11:14:31.420 | at async /vercel/path0/node_modules/next/dist/export/worker.js:304:36
11:14:31.421 | at async Span.traceAsyncFn (/vercel/path0/node_modules/next/dist/trace/trace.js:79:20)

https://nextjs.org/docs/advanced-features/custom-document
vercel/next.js#37911
https://stackoverflow.com/questions/66531551/error-mydocument-getinitialprops-should-resolve-to-an-object-with-a-html