SmartEvent is licensed by the total number of gateways providing logs for correlation, how many gateways is your SmartEvent Server licensed for and are you over the licensed limit? Assuming the SmartEvent Server is a Smart-1, the last two digits of the model number indicate the number of licensed gateways (i.e. 5 for SmartEvent Smart-1 model 205, 50 for model 3050, etc).
If your SmartEvent Server is open hardware/VMWare, run "cplic print" from expert mode on the SmartEvent server and you should see how many gateways you are licensed for in the license SKU. On the lower license levels perhaps there is some kind of daily licensing limit as to the number of logs that can be correlated but I doubt it.
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