This prompt often appears after I use BB VST to generate. Is this problem an error?
How to solve it?

Try these:

Pipeline：

Follow the steps you said. But the same error still occurs

Hi swingbabymix, for these errors it may be easier if you contact our support team directly by either emailing support@pgmusic.com or going to live chat on the website. This way we could look up your records and see exactly what tracks you should have.