I have experienced this in my online earnings journey that some of the forum owners are not willing to allow other forums to promote their forum on their forum and I respect this decision and could be they don't want their competitors to get ahead of them or simply they don't want any other forum advertising on their forum.
Why Some forums Don't Allow Other forum admins to Promote their Forum on Their website?
Why Some forums Don't Allow Other forum admins to Promote their Forum on Their website?