You can check that your client is correctly connecting to the dedicated instance executing the client with "--help", which will display the instance and the account it is connecting to.
$ export METERIAN_ENV=acme
$ export METERIAN_DOMAIN=meterian.uk
$ isaac --help
Meterian ISAAC v1.1.16
© 2017-2021 Meterian Ltd - All rights reserved
--help Displays this help end exits(0)
Meterian servers at https://acme.meterian.io/ are reachable from this system
Meterian servers are authorizing this client for account "QA Account"