You have exceeded your daily logs GB/Day licensing limit within the last 7 days

[khurram]

We are getting below error on FortiAnalyzer and want to know how we can check that why daily logs are exceeding and what is the reason and solution to stop it.

"You have exceeded your daily logs GB/Day licensing limit within the last 7 days"

i have to provide solid reason to customer that why its exceeding.

Appreciate your support.

[nnair]

Dear,
Please check the below link: 
https://community.fortinet.com/t5/FortiAnalyzer/Technical-Note-Minimizing-logging-from-FortiGate-to/...

[Yurisk]

Fortianalyzer does not provide any info regarding this - not what logs are in excess, nor from which Fortigates (the limit is calculated as a cumulative log intake over some time, if serving multiple FGTs). We cannot even know for sure what happens to those excess logs - from Fortinet viewpoint, it is undetermined behavior, so they cannot say if those logs are being dropped or still logged.  

In other words - you don't really have means to answer "why this happens", only as @nnair mentioned, you can try and reduce volume of logs sent to the FAZ until this error message disappears.