'/login' route redirection doesn't work : "Cannot GET /oauth2/default/v1/authorize"

I am using the " @okta/oidc-middleware" in my node.js web app to ensure account management.

My problem is the following :
The oidc connects correctly to okta but when I try the route ‘/login’ of my website, it redirects on a URL starting by URL of my website instead of my okta domain.
So it gives me the error “Cannot GET /oauth2/default/v1/authorize” and if I manually change the URL by starting it with my okta domain, it works great.

I think I have a configuration problem but I can’t fix it !

Thanks for your help