suchefrobaz@gmail.com
Include your SketchUp version and the steps you took. Please don't attach project files unless asked and you are sure they are safe to share.
Support
Talk to the people who build it.
Product questions and mainland China testing inquiries all go to the same place.
Contact
popo_h2o
For mainland China testing inquiries.
Before sending diagnostics
A diagnostic package is created locally and never sent automatically. It can include full model paths, project file names, the current model path, your signer name and recent errors. Open the text file, check it, and remove anything you don't want to share.
Also helpful
Many answers are in the FAQ, and the tutorials cover day-to-day use.