Short list of items to validate:
1. Status of the SLA you are expecting to see, i.e. are they currently being tracked, future sla, etc
2. If on 12.0.03+, does the time filter on the top right of the WebUI dashboard page cover the time frame that the SLA will be tracked in?
3. Is forecasting enabled in the iDash admin tool -> SLA tab?
4. Are there any errors in the error.log files?