IceWarp Mailbox Size

Hi,

Can you please help me with this problem, I feel like my icewarp is using too much space then the outlook.

My E-mail quota is 3 GB, and actualy I am using 2.6 GB acording to the icewarp outlook sync.

But when I go to my user to check the .PST, I check that the PST size is 1.3 GB.

Can you help me finding why IceWarp is show me that is using to much space?