Hi,
The acyba.com website doesn't exist anymore. Please update your Acymailing v8 tot the latest v9.8.0 version, it will resolve your issue.
Regarding your issue on your v5 Acymailing install, we inform you that we have announced many times in the past year that at the end of January 2024, we are stopping support for AcyMailing 5 and that we won't provide support for it after that date.
We have explained how to migrate your installation to version 9 in the following series of articles
https://docs.acymailing.com/setup/migration
https://docs.acymailing.com/setup/installation
Thank you for your understanding!