Adding guest users to project sites in Project Online

[Jakob Rohde]

We have enabled guest users in our O365 tenant, and frequently grant them access to normal SPO sites. But it doesn't seem to be possible to invite guest users to sites created as project sites under PWA, even though the PWA site collection has guest users turned on.

Is it possible to collaborate with partners on projects in Project Online?

[#2]

Unfortunately from a legal perspective you also need a subscription for guest users on sites created as projects sites under the PWA site. During the Ignite 2016 it was announced that a feature would be upcoming that allows you to assign Project subscriptions to external accounts (Azure B2B). It is still in development: https://products.office.com/en-US/business/office-365-roadmap?filters=&featureid=14879