Hello
Joomla 5.4 introduced core changes that are not backward-compatible, which is why some sections of the extension no longer work correctly on Joomla 5.4 / Joomla 6.
Available options:
1/ Restore from a backup taken before upgrading to Joomla 5.4 (recommended, if available)
2/ Wait for an official compatibility update of Ad Agency for Joomla 5.4+
3/ If this is urgent, you may consider hiring a developer to update the extension for Joomla 5.4+ compatibility.
JoomlaArt offers professional Joomla development and migration services here:
https://www.joomlart.com/service/joomla-4-migration-service
Before upgrading Joomla core, we strongly recommend checking extension compatibility and creating a full backup.
We’ll share updates in this forum as soon as Joomla 5.4 / Joomla 6 compatibility is available.