"Steinberg License Engine is not running"

All of a sudden this started happening.

This is terrible. I have deadlines to meet and I can even use Cubase.

for years never had issues. and all of sudden this.

Yes, that sucks…

We can only help you if you provide details, though. Starting with OS, Cubase version, etc.
Have you tried to download the latest Download Assistant? It will automatically update your Activation Manager, too.

correction: this is actually happening to MODX-M plugin only not cubase.

I’m on cubase 13.

latest Mac OS.

Probably restarting the computer, as the dialog says. is a good 1st step to troubleshooting. You didn’t say whether you did that so…

did that already of course

In that case, you should check for the latest firmware and software here, first:

Also, try to reach out for Yamaha support, please.