Supplier cannot see the project

If a supplier user cannot see a project, here are a few basic checks you (the authority) can perform:

1. Has the Supplier user been added to the project?  (Project > Suppliers)
2. Is the Supplier user project access set to YES?  (Project > Suppliers) 
3. Is the Supplier account active?  (Administration > Suppliers)
4. Is the Supplier user Active?  (Administration > Suppliers > Supplier Users)