changed the domain in Joomla
Review the page at https://docs.civicrm.org/sysadmin/en/latest/misc/switch-servers/

Did the directory path change in addition?

Stuff to try:


look at your setting.civicrm.php file for any thing that needs updating
clear out your civicrm cache directory. typically at media/civicrm/templates_c Just get rid of everything in that directory (you can leave the .htaccess). But get rid of everything else including any subdirectories (e.g. en_US) (see above link for info)
if you can access your administrative page check your directories and resource_url settings
rebuild your menu's (described in above url)