There are open periods in company code & for the period to be reloaded

What causes this issue?

The program checked the company codes in questions for open posting
periods in the period to be reloaded.
Open items were found in company code &V1& for account type (or
masking) &V2&.
Following is the key for account types:

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

| Value | Description
| ---------- | -------------------------------------
| + | Valid for all account types
| A | Assets
| C | CO-PA: profitability analysis
| D | Customers
| G | Special Purpose Ledger
| K | Vendors
| M | Materials
| S | G/L accounts

System Response

No data is reloaded.

How to fix this error?

Close the relevant posting periods and/or check your entries.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.