What happened?

1. A new site was developed with a clean install of Joomla 6.0, when going live it was discovered automated updates could not be enabled.

Version

6.0

Expected result

To see Automated Updates are Enabled in the admin dashboard

Actual result

Error Message in a notification box:

Error while registering to automated update service: Invalid JSON body (500).

System Information

Joomla! 6.0.3 Stable [ Kuimarisha ] 17-February-2026 16:00 UTC
PHP Version 8.4.20

Additional Comments

Have tried cache clearing, browsers, removing htaccess, gzip, swapping administrator directory with copy from another site, config permissions, database editing of key, database editing of autoupdate_status, changing update source, trying custom url for updates. Anything to nudge it. A copy of the site moved to another domain has same issue. The copied site was manually updated to 6.1 and issue persists.