Why can't I find the actual period that i want to import on the Import Trial Balance screen?
There are 2 possibilities:
1. The period is not part of the existing periodicity (Historical years, current year, and forecast/budget years), which mean you can not import data for periods which do not exist in the project.
2. The period is not considered as an actual period yet, and still part of the Forecast/Budget's period. To make a forecast period to be an actual period, do the Monthly Rollover until you passed that particular period. To do the Monthly Rollover, navigate to Admin > Monthly Rollover menu. It will show you the current forecast period, and when you click the Execute button, it will start the process to roll over to the next month