They are fussy.I grew one for years in a greenhouse/conservatory and it would grow well for awhile then go semi dormant.And thats the nature of the fern. It might be semi temperate if their is such a term,needing a few months rest.Tropical ferns that need a rest period drive me nuts!
Other possibilitys are,low humidity,bad water, and being an epiphyte your potting soil might be too heavy and water logged.

Likewise. I found them a fussy fern, though members of the Texas Gulf Coast Fern Society (TGCFS Houston Based) do have some luck growing them.