WRITE_ACCESS_DENIED — Error Class PROPERTY, code WRITE_ACCESS_DENIED

The property exists but cannot be written — either it is read-only, or the write was refused at this priority.

Start free BACnet/IP → canonical

Diagnosis

When you hit this

Writing to present-value on an input object. Analog and binary inputs are read-only by design; outputs and values are what you command.
Writing at a priority lower than an existing entry in the priority array, so a higher-priority command already owns the point.
A device configured to reject writes from unknown clients.

Resolution

How to fix it

Command the right object type
Write to Analog Output or Analog Value, not Analog Input. This is the usual mistake.
Read the priority array first
Property 87 shows what is already commanding the point and at what level. Writing below it silently loses.
Release when done
Write null at your priority to relinquish, rather than leaving a stale command holding the point.

Normalization

What Forge does about it

This is a configuration or addressing mistake on the wire, upstream of anything Forge sees. Where Forge helps is the step after you fix it: once the point returns data, its vendor tag name maps to a canonical field automatically, so you do not also have to hand-maintain a name table for every point you just re-addressed.