Adjust Exchange Rate only for selected month

If you have open transactions in the system that are only shipped/received but not invoiced, the system posts some kind of estimation that will be corrected once the real value is determined. This correction is posted as close as possible to the original date of the estimation posting based on the General Ledger Setup. If the date of the correction posting is not allowed by the user setup, you will get this error message.

Well, if the issue is really related to what I think of, then the answer to your question depends on your situation and what you want to allow the system to do. I think the easiest way to bypass this error is to set the allowed range in General Ledger Setup to the same range than your User Setup. But I'm not sure if this is the best way since there's more to be considered, e.g. your period closing rules, where do the open transactions come from, and so on.