Hi navongol
T4 Builder is not ready for Joomla 4 yet, the team are working hard on this update and do hope to release new version within this week.
Pls check the update status here: https://www.joomlart.com/joomla4-status/index.php?group=jaec
Regards
There is issue with the JA Extension Manager
Not responding not working properly
endless checking ~
check update not responding
navongol I replied in that topic, kindly follow it.