Dear Cristina,
check your webserver logs for size - I also did the upgrade to 2.4.8.5 to run OJS in PHP 7 and in my case these php warnings were piling up in the server logs and the logs can become huge. See these posts for the fix: Ojs 2.4.8-4 is compatible with php 7.3? - #12 by AlesKladnik, PHP 7 warnings filling up error log after upgrade to 2.4.8.4
If you downloaded the code from git using ojs-stable-2_4_8 branch this should be fixed, but the code in the OJS download page is missing this fix. This is the fixed file: pkp-lib/PKPApplication.inc.php at ojs-stable-2_4_8 · pkp/pkp-lib · GitHub
@asmecher Alec, is it possible to update the Download OJS 2.4.8-5 link with the lastest changes in the ojs-stable-2_4_8 branch on git?
Regards, Ales