Error when saving content for pages in subfolders

Error label appears, nothing in log (i switched on debug mode in config.php), just:

[2017-09-06 16:35:38] Info: Matched route “GET_”.
[2017-09-06 16:35:38] Info: Matched route “GET_”.
[2017-09-06 16:35:47] Info: Matched route “POST_”.
[2017-09-06 16:35:51] Info: Matched route “POST_”.
[2017-09-06 16:35:59] Info: Matched route “POST_”.
[2017-09-06 16:36:00] Info: Matched route “POST_”.
[2017-09-06 16:36:16] Info: Matched route “POST_”.
[2017-09-06 16:36:19] Info: Matched route “GET_”.
[2017-09-06 16:36:39] Info: Matched route “GET_”.

What can cause the problem?

What error are you getting? After which action?

After any change and after publish. The only comment is “#2 Próba zapisania wprowadzonych zmian treści nie powiodła się. Ponawianie…” (in polish it means: Error when trying to save content)

Method POST: http://www.mydomain.com/_test/sitecake/2.4.5/src/app.php?service=_content&action=save returns 400

Error occurs on page:
http://www.mydomain.com/_test/sitecake.php?scpage=faq/index.html

The same action for page located in main directory works fine, eg: http://www.mydomain.com/_test/sitecake.php?scpage=index.html

Can you check response from AJAX call when you get error for http://www.mydomain.com/_test/sitecake/2.4.5/src/app.php?service=_content&action=save and post it here?
You can check it through firebug if using firefox or developer tools if using chrome

{“status”:-1,“code”:400,“errMessage”:“400 Bad Request : Page ID is missing”,“trace”:[{“file”:"/_test/sitecake/2.4.5/src/Sitecake/Dispatcher.php",“line”:78,“function”:“save”,“class”:“Sitecake\Services\Content\ContentService”,“type”:"-\u003E",“args”:“Sitecake\Dispatcher::response((object), \u0027save\u0027, (object))”},{“file”:"/_test/sitecake/2.4.5/src/Sitecake/Dispatcher.php",“line”:72,“function”:“response”,“class”:“Sitecake\Dispatcher”,“type”:"-\u003E",“args”:“Sitecake\Dispatcher::execute((object), \u0027save\u0027, (object))”},{“file”:"/_test/sitecake/2.4.5/src/Sitecake/Dispatcher.php",“line”:43,“function”:“execute”,“class”:“Sitecake\Dispatcher”,“type”:"-\u003E",“args”:“Sitecake\Dispatcher::dispatch((object))”},{“file”:"/_test/sitecake/2.4.5/src/app.php",“line”:16,“function”:“dispatch”,“class”:“Sitecake\Dispatcher”,“type”:"-\u003E",“args”:"{closure}"},{“file”:"/_test/sitecake/2.4.5/vendor/symfony/http-kernel/HttpKernel.php",“line”:153,“function”:“call_user_func_array”,“args”:“Symfony\Component\HttpKernel\HttpKernel::handleRaw((object), (int) 1)”},{“file”:"/_test/sitecake/2.4.5/vendor/symfony/http-kernel/HttpKernel.php",“line”:68,“function”:“handleRaw”,“class”:“Symfony\Component\HttpKernel\HttpKernel”,“type”:"-\u003E",“args”:“Symfony\Component\HttpKernel\HttpKernel::handle((object), (int) 1, true)”},{“file”:"/_test/sitecake/2.4.5/vendor/silex/silex/src/Silex/Application.php",“line”:496,“function”:“handle”,“class”:“Symfony\Component\HttpKernel\HttpKernel”,“type”:"-\u003E",“args”:“Silex\Application::handle((object))”},{“file”:"/_test/sitecake/2.4.5/vendor/silex/silex/src/Silex/Application.php",“line”:477,“function”:“handle”,“class”:“Silex\Application”,“type”:"-\u003E",“args”:“Silex\Application::run()”},{“file”:"/_test/sitecake/2.4.5/src/app.php",“line”:43,“function”:“run”,“class”:“Silex\Application”,“type”:"-\u003E",“args”:"[main]"}]}

Hi, did you create .scpages file and add faq/ line to it? Check this link for details about .scpages file Page Manager Is Finally Available.