You can put Hardcane Dendrobium in the search box to find past posts but they probably will not be much help as they relate mostly to growing conditions in the USA.
You need instructions specific to tropical lowland climate conditions.
Where are you trying to grow your Dendrobium, perhaps you have it in too much shade?

Almost all fertilizers are colored so that nursery workers and farmers can see if the injectors in their automatic fertilizing systems are working properly. No green/blue = no fertiizer mixed with the water.

Nearly all dendrobiums bloom only once a year for a couple of months. Once the blooms are gone you have to wait for the same time next year. The environmental change from where the new plants were to where you put them often shocks the plants into early flower death. A change in the weather (reduced humidity for a few days) can do the same thing. Newly purchased dendrobiums often lose some leaves as well. The new growth next year generaly keeps its leaves and flowers better in your location.