When I try to login into SUBdomain dashboard it will not be possible to see administration panel. How is it possible or functions.php problem?
Is that account you are logging in with an admin/editor account? If it is just a subscriber account, usually they see just their profile screen. This is what WP normally does.
If however you are using an admin/editor account and not seeing the main overview dashboard, it could be a plugin that is protecting the admin dashboard. Hard to say without knowing what all the plugins do.
One way to check is to disable all your plugins, try to login again and see if it fixes the problem. If it does, try re-enabling each plugin one by one until you can’t login to the dashboard again. Then you will know which plugin is causing the problem.
I have tested an issue.
When I login directly (Multi WP site) into SUBdomain account, it will be seen administration.
When I login into WP Multisite and click
Sites >Dashboard it will vanish administration.
Maybe you can help more on this problem. Is this related to functions.php and specific to the theme?
You say “vanish” but does that mean it is a white blank page? Or is it showing your something in wordpress, but has no widgets or anything? You don’t see any menus or anything?
If you see something, perhaps tell us what you see, or if you can, post a screenshot?
You might have a plugin (or the theme in the functions.php file) that is erroring out because it wasn’t meant to work in a multi-site environment. Again, I suggest you disable all your plugins and go to a default theme and see if your multi-site works again. Also be sure to check your site’s error logs. It might be as simple as updating a single function in your functions.php or disabling a problematic plugin.
I’m checking again.
Network Admin > Sites > Dashboard
It will not show an admin page on the left-hand side. Any widgets…just a website.