Note: the translator tool does not use legacy "interwiki" codes of Wikipedia (like "zh-classical"), but only conforming BCP 47 codes ("lzh", from ISO 639-3 is what is intended).
these legacy interwikis codes are still recognized as prefixes of pagenames within wikipages, and as subdomain name, but even the "lzh" subdomain name is also recognized and "zh-classical" is now purely internal to Wikimedia wikis and are in transition and are not used as language code suffixes in page names (after a "/") for the translator tool
So "zh-classical"" is now an old alias of "lzh", even if the internal database name of the wiki is still "zh-classicalwiki" (this internal name has no influence for the navigation, but only for restricted tools used by server admins). Use "lzh" everywhere you can in wiki pages.
I fixed that, because it was impossible to translate the requested language