Why am I getting the message 'Your Illustrator build has expired.' when I try to open AI Beta?

[Marnox5]

I've just downloaded Illustrator Beta but when I try to open it, a message pops up saying:

'Your Illustrator build has expired."
accompanied by a button saying 'Quit Illustrator'.

There's no option other than to press the button.
What's going on?

 

 

[Jess Telmanik]

You may be trying to open an expired Beta Build. Check for an updated Beta build in the Creative Cloud Desktop App.

Apps > Updates > "Check for Updates"