I assume that you have a Kenmore or LG French door refrigerator. The ER FF error code is common on those types of refrigerators.
The ER FF error code indicates that the electronic control board detects a problem with the freezer fan (evaporator fan). The evaporator fan is fairly difficult to access in this type of refrigerator. Here is a link for a previous answer that provides access information for this part of the refrigerator:
There display on my Kenmore Elite Bottom freezer reads ER 1F. Why and how do I fix it? The Ice maker will not work either.
If you are able to unplug the refrigerator and access the freezer fan using the procedure shown in that previous answer, you may be able to determine whether this component is bad. The control board depends on a feedback signal from the evaporator fan motor to determine whether it is working properly. There is a possibility that you have a wiring failure or a bad control board that is causing this ER FF code.
If you need more help with this problem, reply with additional details and the full model number of your refrigerator. We will assist you further once we receive more information.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services