I think I might have this problem, or at least a similar one. It seems like my sims can't give massage to customers if I place the portable massage table off-lot (outside of the lot boarders), but it works if I place it on-lot. For example, if my sim goes to the Romance Festival and put the massage table down at the festival grounds the option to give massages is greyed-out and if I hover over the option it says that there are no potential customers nearby (even though there are a lot of sims at the festival), but if I put the massage table on the lot (Planet Honey-Pop in this case), next to the festival grounds, the option to give massages is available.
