The "login is not allowed" page should not be a separate endpoint

[krzys-h]

Noticed while testing #93

Reproduction steps:

1. Try to access the login page from a disallowed IP
2. The error page appears
3. Switch to using an allowed IP
4. Refresh the page

Expected behavior:
The login page now appears

Actual behavior:
The error stays on the screen, even though you are now using a whitelisted IP. You have to close the page and reopen the login page manually.