Hello Ahmed,
There are several moving parts here. It's going to be the most efficient use of your time to reach out to Support.
The bulk of your current issue appears to be certificates. Your agent reporting from 1969 likely either didn't get all of the certificates, or can't connect fully to the LEM. The existing agents you will want to clear the Agent Certificates.
Troubleshooting LEM Agent Connections - SolarWinds Worldwide, LLC. Help and Support
If you have many agents that would be difficult to touch directly then Support should be able to assist with this.
You can't set up a new LEM and expect the nodes will connect to the new appliance without any additional configuration due to certificates tying the agents to a LEM deployment to specifically thwart this type of scenario.