Issue Not getting a valid SSL certificate when accessing site from local network

[AdrianC]

I used to have a public static ip that was received when server directly made a PPPoE connection to my ISP...

Now I switched to router being the one doing the pppoe connection and server now has a LOCAL ip,
In Plesk under this local ip (e.g 192.168.1.88), I filled the public ip field too.
I reconfigured the hosts, removed old IP, etc.

But I noticed when I access https://my-site.tld from the same local network, the browser is not returning a valid ssl ce certificate, I clicked next to site name in browser and from what I can tell, no cert is received at all.

From outside the network it works OK, a valid cert is received.
I tried regenerating the LetsEncrypt cert, it didn't help.

I want to make sure it is not a Plesk thing first, but It might be my router, a MikroTik that has 3 different pppoe connections on local network; and has routes given, so each pppoe is used by a different computer, but I am kind of lost.

Any ideas ?

 

[Hex]

I am kind of lost.

That's makes us two


Despite you didn't provide any information about your setup but I think you need to use a separate pppoe connection to establish a secure HTTPS connection with your local hosted plesk website.
It's like you're trying to call yourself with your own mobile but the line is busy. you need to call from another phone.

 

[AdrianC]

I didn’t think any other details are needed, using latest plesk on CentOS if it matters.

I still think it should work ...

The two are on separate pppoe (different public ip) but on same router and they can “see” each other on local IP 192.168.1.X

Edit: At this point I think is a routing/router problem, from local network I always reach the router instead of server, that is why SSL was missing, I need to solve that first :/