Nicko Che

Oh, excuse me )
But it does not matter – problem is still here

Thank you very much, frene7ik!
Your solve really works. But for page redirecting need correct the next ELSEIF, by analogy of your code:

...
            } elseif (isset($oPageParams->query_vars['pagename'])) {
                //change by Che 17-05-13
                //$oObject = get_page_by_title($oPageParams->query_vars['pagename']);
                $oObject = get_page_by_path($oPageParams->query_vars['pagename']);
...

And it perfect works with permalinks and with home page (do not check with default URLs)
This solution completely satisfied me. New bugs not found for now. So,
https://expertbaby.ru/nashi-kursyi/sekretyi-vospitaniya-otvetstvennogo-rebenka/ is redirecting to https://expertbaby.ru/blockedpage/

I found something like that:
Redirect works with a default URL of post/page like “site/?p=123” and does not work with a permanent link like “site/link_of_page”.

Dear Alex, do you have any thoughts on this?
Do you need any more information?
Perhaps if we think about it all together, the right solution will come faster? )

OK, but sorry my google english )

There is a page designed for a group of users – https://expertbaby.ru/nashi-kursyi/sekretyi-vospitaniya-otvetstvennogo-rebenka/
(By the way, here is protected only by the main text, but not the sidebar, and it may be unique for this page.)
Here, the page where I need to redirect unauthorized user – https://expertbaby.ru/blockedpage/.
Now everything is set up that way, but as you can see, nothing works.

And no matter what the settings are set to Redirect User. Does not work redirect to the home page or a custom page or a custom URL.

I read somewhere and tried to fix for an experiment – line 298 of user-access-manager.php:
add_action ('template_redirect', array ($oUserAccessManager, 'redirect'), 10);
the redirection works, but found a problem with a page templates – always use a basic template, regardless of the selected template of the page.

In all other respects your plugin works fine, thank you very much!

Sorry, dear GM_Alex, redirect user does not work with UAM 1.2.4.3