Hi Mohammed,
Few things here. What we need to see is a screenshot of your Archive and Purge rules, not the options manager options. Please show us the details of the archive and purge rule for requests/incidents etc. Typically the problem you are seeing happens when folks set up an archive and purge rule to purge data that is more then X number of days old - meaning that it was closed X number of days ago, and they are checking that ticket more than X number of days later, thus its no longer in the system as it was archived/purged by the rule.
As a side note, I wanted to also mention here that the release you are on (12.5) has been out of support for nearly 4 years now. I would highly recommend that you upgrade to the latest release of the product (14.1.03) as soon as possible.
Thanks,
Jon I.