@Sinto001
Your problem comes from another application being installed on your server that is incorrectly redirecting osclass links to it's own.
This is not osclass issue. Install osclass on standalone server or subdomain.

I don't know my redirecting issue is due to some missing files as told by hosting provider support. Somehow the redirections has stopped but the upgrading issue remains the site is upgrading for more than hours not completing it anyway.

@Sinto001
Redirect issue is not fixed on your site.
Until you will have it on functional space installed, it does not make sense to discuss anymore.

I checked there is no issues with admin login like before. only problem is now i am logged in and cannot log out as admin and the upgrade page with upgrade button appears every time i click log out.

Click on publish button as not-logged user.

Click on publish button as not-logged user.

I am getting page of login with message only registered user can publish ads.

I got error 404.

I got error 404.

Modern browsers clears the cache and cookies very late..

I have inspected the upgrade page and the console option shows some errors pls check the snapshot

Make sure you have https setup properly in config.php
You could also open that php file from console to complete manually

Make sure you have https setup properly in config.php
You could also open that php file from console to complete manually

That worked upgrade completed. But the user mode cannot upload images there is no options

Fix all errors you have in console and error log.

Can you tell what other errors are there and how to fix it just like you suggested about config.php . I have no experience reading error logs and resolving it.