If the file has been translated successfully in Language Studio but doesn't appear in MemoQ. It is possible, if a large file or where there has been busy traffic in Language Studio, that the file took longer than usual to translate, resulting in MemoQ's connection to Language Studio timing out.
If this ever the case, it helps to have a longer Job Timeout in your Language Studio MemoQ settings, to avoid timeout.
This means, instead of having a ONE hour time window, a longer timeout window is given.