Not sure if you're still active on this discussion but I also have a problem with the language customization. This is what I see when I turn on the debugging:
·line 446 of /lib/dml/moodle_database.php: dml_write_exception thrown
·line 1080 of /lib/dml/mysqli_native_moodle_database.php: call to moodle_database->query_end()
·line 1122 of /lib/dml/mysqli_native_moodle_database.php: call to mysqli_native_moodle_database->insert_record_raw()
·line 186 of /admin/tool/customlang/locallib.php: call to mysqli_native_moodle_database->insert_record()
·line 60 of /admin/tool/customlang/index.php: call to tool_customlang_utils::checkout()
I did not install any plugins lately because I recently created the Moodle, I only added the theme essential. Do you have any idea how I can solve this?
please update to the latest version of Essential.
This was indeed a bug with the notification language handling in a previous version, which has now been replaced with proper multilang filtering.
The problem with language customization only occurs when editing languages other than english, and the new version of Essential will resolve this.
Thank you for your response. I'm trying to update the theme but he now gives an error that the plugin files are not writeable (not sure if this is the right translation). So have to fix that first!