When I go to Store settings, among other pages it always redirect to dashboard. no errors browser, no errors in log files, so I dont know how to even get hints. any suggestion on how I can debug this please?
I always start by looking at browser xhr requests with magento errors enabled.
In chrome for example
Chrome currently has a solution built in.
Use CTRL+SHIFT+I (or navigate to Current Page Control > Developer > Developer Tools. In the newer versions of Chrome, click the Wrench icon > Tools > Developer Tools.) to enable the Developer Tools.
From within the developer tools click on the Network button. If it isn't already, enable it for the session or always. Click the "XHR" sub-button.
Initiate a button click on store settings.
You will see items begin to show up in the left column under "Resources".
Click the resource and there are 2 tabs showing the headers and return content.
Look for anything that returns a 500 code or anything a bit different. You may need to toggle persist logs. Clear and the try again.
Check console if you haven't already for missing assets