[ESMC 7 can't talk to underlying CentOS (appliance) How to resolve?]

Hmm, so from the date that ESET on CentOS became isolated, was when I added new certs in 2019.
I will look on the procedure to create an installer - but remember, I can't push this from the ESMC server, as it can't see it

- and I'm not very linux savvy. Is there a way to treat the Appliance OS like a 'Rogue' compuetr to push an installer to it?
(and thanks)

[ESMC 7 can't talk to underlying CentOS (appliance) How to resolve?]

Thanks for the suggestion to check that Marcos,  I was able to locate, copy and then open the status.html file, to see that the issue is related to Replication Security:

Remote machine certificate is not trusted because signing certificates (CAs) are not trusted or found in system/agent database
Check if signing certificate authority was used during installation of agent or installed in system

What's the quickest way out of here, - can I use the certificates I recently backed up or can I otherwise push a trusted Agent into the ESET Appliance OS?
 

[ESMC 7 can't talk to underlying CentOS (appliance) How to resolve?]

I'm using the ESMC CentOS appliance, it's been running for over a year.

Logging into the ESMC server I see the CentOS machine in Linux Computer list, but, shows it was last connected over a year ago, and so, I can't use ESMC server to  use Client Task to command updates to CentOS or update the ESET Agent.

What might be reason that CentOS ESET Agent can't connect?
Certs? 
Is there a way to trigger ESET agent in the appliance?
 

My overarching task is to update 'everything': CentOS, ESMC to latest 7.3, then the clients.
Versions:
CentOS (64-bit), Current Version 7.5.1804
ESET Security Management Center (Server), Version 7.0 (7.0.471.0)
ESET Security Management Center (Web Console), Version 7.0 (7.0.429.0)
Agent Current Version everywhere other than CentOs: 7.1.2053.0
From VSphere, in the VM Appliance window, I see Server & Agent Version 7.0471