Hello Ahmed,
These issues can take time to diagnose. If you're able to connect remotely with a Support representative they are likely to be able to help you in a more timely fashion. That being said, the first thing you will want to verify is resources:
Plan your deployment - SolarWinds Worldwide, LLC. Help and Support
If your LEM deployment is under powered for what you're trying to do or your resources are not reserved, then you're going to run into plenty of issues with slowness.
Additionally if you are able to get into the console, you will likely want to disable all rules (and be sure to Activate Rules) until you can diagnose the issue. If you have a lot of active rules (or a few that are very active) then you want to get these disabled so that you can tune them and work out from there.
For additional reading:
LEM goes down daily and requires constant restarts - SolarWinds Worldwide, LLC. Help and Support