Logging in – getting blank page

I occasionally get a blank page when I update something in WP, but I’ve been ignoring this and working around it.

But now when I log into WP admin I immediately get sent to a blank page. Going back or re-entering the URL just takes me back to the login page to start over. Refresh just refreshes my blank page.

Does anyone know why this is happening and if there’s a fix or a workaround?

Thanks in advance!