Most probably is a Theme problem. Go to project settings - see if theme is set. If not set it otherwise change it and set it again. Reload project, try to compile again.
If this doesn’t work maybe it is a project within a project case.
Most probably is a Theme problem. Go to project settings - see if theme is set. If not set it otherwise change it and set it again. Reload project, try to compile again.
If this doesn’t work maybe it is a project within a project case.