I encountered this error when using UiPath Community edition.
I was trying to define an “unattended” robot to use with a “Process” created from UiPath Studio.
The Community Edition provides 2 Studio, 2 Attended and 1 UnAttended licence.
It made no sense to me why this error was encountered.
I resolved it, by selecting the “Service” on the Cloud Portal Page and clicking “Edit”.
This shows the robots licences available and how many are allocated to “THIS” service.
In Community edition, it is “Possible” to define more than one service, so the licences are available but not “Allocated” by default.
I updated the Allocation of “Unattended” robots for my service. With this change made, I was then able to create a robot of type “Unattended”.
I am posting this message for the benefit of others who may encounter the same error and search the forum.