I have just upgraded to 3.3 and can no longer access the Language Customization English (en). It is there, however, when selecting it, it does nothing.
This is causing me a major issue now - have I posted this question in the right location or is there a better way to get this problem fixed via another forum?
Luke, please can you clarify what you mean by "when selecting it, it does nothing."?
Also Janek, I don't understand "Can't open both in the admin dashboard." Perhaps you can provide a screenshot to explain things.
How about trying logging in as an admin on https://demo.moodle.net/ and accessing lang customisation there?
PS I'm moving this discussion to the Languages forum where the language experts hang out...