Connect : NOMAD_UPSTREAM_* not populated?

NOMAD_UPSTREAM_* variables are present like:

NOMAD_UPSTREAM_ADDR_wallabag_postgres=127.0.0.1:5432

but I can’t connect to this.

If I look in nomad for the postgres IP host and port, I can connect to postgres
If I look in nomad for the connect related service for postgres, I can’t connect to postgres.

I would have thought that mapped port would be in this case 5432 and not an exotical port

Ports
Name 	                        Host Address 	    Mapped Port
connect-proxy-wallabag-back 	XX.XX.XX.XX:26658 	26658
postgres 	                    XX.XX.XX.XX:23880 	5432

I tried to add a local_service_port as mentionned here : Port mapping with Nomad and Consul Connect - #2 by awarner-greshamtech but it seems without impacts.