Can’t login using wp-admin

So there has been a lot of people with this issue I see, but the solution always seems to come back in the form of private messages. The issue is the same as many others, when trying to login to the WP dashboard, instead of being taken to the login screen, we are redirected to our sites homepage.

I understand you can disable the plugin by renaming it and then logging in, that said I can’t hand over a site to a client like that.

We want to buy the Mailchimp plugin to tie into our clients list, but we cannot until this dashboard admin issue is resolved..

Hope to hear back from someone soon