The post report is not available once it is closed.

It is possible to print a copy of the Journal Entry batch that was created from the post, which can be found in the General Ledger.
    To print a Journal Entry Batch: 
    1. Go to the General Ledger module
    2. Select Reports > Journal and Batch Reports
    3. Highlight Batch Detail Report and click New
    4. On the Filters tab > Batches row > highlight All under the Include Column
    5. Click the drop down arrow and choose Selected
    6. In the window that opens enter the desired Batch number and click OK
    7. Select Preview to assure it is the correct batch
    8. Click on the Print Icon
    You can also print the Batch Detail Report directly from the Journal Entry:
    1. Go to the General Ledger module
    2. Select Journal Entry
    3. Open the journal entry that you need to reprint
    4. Select File > Print