When you go to create a new SL account you may get an error while saving the SL account record that "NL account is not a balance sheet account"
When creating a new Sales Ledger account you might encounter an error stating that "Control account is not a balance sheet account". If you get this message it is normally because the SL account type entered on the new SL account is expecting a balance sheet control account and the NL control entered is a profit and loss as in the example below:
If you are creating a new credit (customer) account then the NL control should be a balance sheet account and if you are creating a new Internal account then the NL control tends to be a profit and loss account.
This is setup in account types and below highlighted fields control this feature. This setup should not be changed without consultation with Systime. Below screenshot is only to explain the issue. As shown in below screenshot if you need to create an account which is of credit (customer) type then the control account must be a balance sheet control account, but if it is internal it can be any but usually it is setup as profit & loss account code to directly debit the expenses because internal SL accounts generally are not receivables.
You can also get an error if you try to create a new SL account that the account type entered on the new account is expecting a profit and loss account and the NL control entered is a balance sheet account opposite to the example above. That might be due to the reason that your system is configured to have certain SL account types to be created only with Profit & Loss account types but that situation is very rare.