I have been invited to a Campaign but it is "out of keys".

Contact support if the Campaign is "out of keys".

If a Campaign you have been invited to is "out of keys" contact our support and we can try to forward the issue to the Game Studio to check if they can add more keys to it.

Unfortunately, it is not guaranteed that this can happen as this is about the Game Studio and the Platform involved.

You won't need to worry about the situation affecting you negatively as this is not going to impact your Campaign Completion Rate (CCR).