Is there any changes done in OKTA developer tool platform recently? where in they have cancelled out to get the Admin console dashboard?

I’m build a capstone spring boot microservice application, and wanted to incorporate Authentication feature using OKTA Auth OIDC. But I’m not finding the options which are available in admin console, in developer console.

Note: my role is Admin.
I’ve not got any email after verification email.

When I try to login through here, https://.okta.com/admin OR https://.okta.com/login/default
Showing as “Unable to sign in”.