If you see the below error while attempting to import an Auto-Reversing manual journal, one of the periods could be locked, likely the period the journal needs to reverse into.
 
 
For an Auto-Reversing manual journal to import successfully, both the posting and reversing periods need to be open.
If the reversing period is closed the import is not able to be posted as it does not see the posting date as valid due to it not having an open reference.
 
To amend this, navigate to Periods and locate and drill into the relevant period. Ensure the lock icon is displayed on your screen or the period won't be visible.
 
Select the ellipsis and Unlock.​
 
After reloading your session, the journal can be imported successfully.