[mosquitto-dev] PUBREL

[Aaron Chappelle <achappelle@xxxxxxxxx>]

I'm getting a lot of broker PUBREL warnings that won't quit.

Warning: Received PUBREL from [client-name] for an unknown packet identifier 6668.

It seems to be happening when my embedded system is coming up... e.g. broker is launching and clients are coming up.... messages start flowing but I very quickly get this warning.

I have clients using clean sessions, and messages being sent at QOS level 2. Persistence is in memory on client and broker.

I'm just starting to look into this and will turn logging up to understand it better, but wanted to ask if anyone could think of some reasons this would occur.

I was thinking one scenario could be said client disconnected before a PUBREL was sent... when it reconnected with a clean session it tried to send its PUBREL but now the broker didn't have record of said packet id.  I still need to verify there was a disconnect though, and then why.

Any thoughts?