91005: Presence state out of sync

The presence set held by the client no longer matched the state on Ably. The presence members are re-synchronized so the two are brought back into agreement.

What you should do

Wait for the channel to return to the attached state before reading the presence set, at which point the SDK re-synchronizes it. If you need a result immediately and can accept stale data, read the presence set with waitForSync disabled, which returns the last known members rather than the current set.

Why it happens

The presence set was read while the channel was suspended, so it could not be guaranteed current. While the channel is suspended the client's presence set can drift from the state on Ably, until the channel reattaches and re-synchronizes.

What you'll see

The error is reported with code 91005 and HTTP status 400. The message is Presence state is out of sync due to channel being in the SUSPENDED state.