40165: Channel mode not requested when attaching

Publishing a message, object, or annotation — or entering presence — was rejected because the client did not request the matching channel mode when it attached. The credentials permit the operation; the mode that enables it was not requested.

What you should do

Update the client so that when it attaches to the channel it requests the channel mode the operation needs. The error message names the operation that was refused — most commonly, publishing a message needs the PUBLISH mode, and entering, updating, or leaving presence needs the PRESENCE mode.

This is not a capability problem, so changing the token or key's capability will not help — the credentials already grant the operation.

Why it happens

This error means the channel mode required to perform the operation was not among those the client requested when it attached — either because it requested a narrower set of modes (for example attaching to subscribe only and then publishing), or because the mode is not one of the defaults applied when no modes are specified. The credentials grant the operation; only the attach was missing the mode, so the fix is to request the required mode when attaching rather than to widen the credentials.

What you'll see

The error is reported with code 40165 and HTTP status 401. The message names the operation and the missing mode, for example Unable to publish a message as client did not request the PUBLISH mode when attaching or Unable to enter, update or leave presence as client did not request the PRESENCE mode when attaching; the object and annotation variants name the OBJECT_PUBLISH and ANNOTATION_PUBLISH modes.