How to provide login credentials for Google OpenID Connect for Site's Homepage

We are using OJS (PHP version 7.4.33). Our site is

We are hosting 20 journals. We have just enabled Google OpenID Connect for each of the journals. After that both the Register and Login page of the site’s homepage shows “Incorrect OpenID plugin configuration!”. However, the Register/Login pages of all journals are working fine. In reality, the OpenID Authentication Plugin does not offer a ‘settings’ option for the main site, but offers that for all journal pages. So, we were able to provide login credentials only for the journal pages, but not for the main page.

Any suggestion on how we can provide login credentials for Google OpenID connect for the site’s homepage?