For reference, the english translation of the error seems to be:
Bad username given Cannot look for contributions without a user or with a user that does not exist.
For comparision, normal contribs works fine https://zh.wikipedia.org/w/index.php?title=Special:%E7%94%A8%E6%88%B7%E8%B4%A1%E7%8C%AE&target=%E3%81%A0%EF%BC%8A%E3%81%9C&uselang=en
This has nothing to do with Japanese characters, it's a mobile "Special:Contributions" page issue. Consider removing &target= and replace it with /.
This will be resolved by T122305: [EPIC] Make Special:Contributions in core mobile friendly