A few languages (ar, arz, ko, lrc, ur) have localized the special page name "OAuth", which means that in these languages requests to Special:OAuth result in redirects. This breaks OAuth-signed requests to Special:OAuth/identify, unless they use the localized name, and in general developers shouldn't be expected to be aware of that.

To reduce confusion, starting next week special page name localization will be disabled for Special:OAuth when the request is OAuth-signed, which means that sending requests to Special:OAuth/identify will always work, and sending requests to localized versions (such as 특수:MWO인증/identify on kowiki) will stop working. If you have been doing the latter, you need to update your code.