I’ve a very old .NET Webforms application which was using old-fashioned forms authentication. I have sucessfully migrated the whole authentication mechanism to .NET Identity along with OWIN middleware. Everything works just as expected (2fa is also working as a charm). I’ve just one question – I’m completly unsure on how to localize error messages : such as e-mail is required or this user id is already taken. The web.config for this app is set to support PL culture and all external components (such as Devexpress) properly adhere to this setting.

I was trying to set proper culture in the owin app (in my Startup class) but still all messages are displayed in English.

I was also trying to follow some tutorials – but still no go.

Kind regards,
Jack