Your approach is not correct. Your Deposit for rent account cannot be a cash account because money cannot be moved into or out of it for other purposes. Cash accounts include checking accounts, petty cash, credits cards, savings accounts, PayPal accounts and such.
Since your deposit cannot be a cash account, it cannot be involved in transfers. You will need to delete that transaction.
You have a couple choices how to handle this. The best would probably be to create an asset account Deposit for rent. Spend Money from a cash account and allocate to this asset account. If both advance rent and the 3-month deposit were paid at the same time, use two lines on the payment voucher and assign the current rent to a Rent expense account. Your deposit is an asset because it belongs to you, even though held by the landlord, and will help you generate income in the future.
Another option is to establish your landlord as a Supplier and allocate the deposit to Accounts payable and the landlord’s subaccount. Do not indicate any purchase invoice. Because there are no open purchase invoices for the landlord, your deposit will be posted to Supplier credits automatically and remain associated with the landlord until future transactions involve the landlord. Read about that here: [16.7.73] Categorization against customer and supplier accounts more intuitive - #16 by maarten
Your many recent questions on the forum suggest you are new to accounting. I recommend some background reading to gain familiarity with appropriate procedures of double-entry accounting. You might start here: http://www.accountingcoach.com.