If you choose the category of the second level in the search or in the ad as in the photo

When you switch to page 2,3,4, etc I get an error
Why? How to fix it?

Search

Error

So only on 2 categories of level

If will remove from the browser string avtomobili , at the address site.com/transport the transition to 2,3,4 page is running well

@san37
I am pretty sure you already know I cannot find what cause problem from images.

I sent you a personal website address

@san37
Tested and could not get any problem.

browse by categories which are listed in the ad and in the search under price and then move on to 2 , 3, and 4 , it will error out
I'm not making this up,help to solve the problem

@san37
Did not get such issue.
But you can try to make sure iPage is not passed to url.
Go to file search_list.php

Find:
<?php echo osc_search_url(array('sCategory' => osc_item_category_id())); ?>
Replace with:
<?php echo osc_search_url(array('sCategory' => osc_item_category_id(), 'iPage' => '')); ?>
(there are 2 occurences, replace both)

@san37
Ah now I got what is issue, not sure why you hightlight links that are not related to problem.
Url you are trying to open must be opened, it is osclass URL.
If not, contact your hosting provider or disable friendly URLs.

You can see i.e. here:
http://zara.mb-themes.com/for-sale/2

On parent category I also have no problems
But when you get down on the category 2 level , with links in the ad or links in the search on the category of the second level

http://zara.mb-themes.com/for-sale/mobile-phones

Add on your site ads, and check whether to work for you
http://zara.mb-themes.com/for-sale/mobile-phones/2
http://zara.mb-themes.com/for-sale/mobile-phones/3

@san37
What do you think you are doing?

http://zara.mb-themes.com/for-sale/mobile-phones

1) you can clearly see there is only 1 page at bottom, there is no page 2 at pagination
2) even you open page 2, no error 404 is thrown, it shows there are no items on that page (link)

See what works for you

I fixed the code in search-list , but did not help
Write your hosting provider

the hosting provider wrote that not know what is the reason

So how do I fix ?

the response from the provider

the download site is trying to access the next file:
site.com/oc-includes/osclass/gui/css/jquery-ui/jquery-ui-1.8.20.custom.css
but on Your website in a folder site.com/oc-includes/osclass/gui/css no file and folder /jquery-ui/jquery-ui-1.8.20.custom.css