Attempting to bridge two MQTT brokers

I’m using the built-in Mosquitto addon, albeit an older version, using active: true and the supplementary .conf file you have to make

connection bridge-01
address 192.168.1.2:1883
topic # out 0
topic # in 0

results in socket errors (ie the remote broker connecting and disconnecting)

connection bridge-01
address 192.168.1.2:1883
topic # out 0
topic # in 0
try_private false
notifications false
bridge_attempt_unsubscribe true

so does the above

any ideas why?!

many thanks!!

(P.S. Would also happily use nodered instead but can’t find a flow, the adafruit one isn’t a good one, I found that on Google)