Alerter on Postgres

Alerter on Postgres

HI. 
We have set up an alerter in Postgres (15) on linux ubuntu 22.04. 
The alerter works when we listen in psql on the server, but placing the Unidac alerter on our server application doesnt seem to do anything.
I have put log messages in both the onerror and onevent and get nothing back.
Any ideas please?
thanks