Thank you for reporting the problem. Is this the first time you setup the sync-ed folders? If not, did it work before? If it worked before, please restart DriveHQ FileManager and check if it works fine again or not.
You mentioned you have DriveHQ FileManager running on two Windows 10 PCs. Did you configure them to sync the same cloud folder? If both PC sync to the same cloud folder, then the local folders on the two PC should also be sync-ed. DriveHQ FileManager supports real-time synchronization and scheduled synchronization. Please make sure your sync tasks are real-time if you want files to be sync-ed ASAP.
You mentioned that “When files are uploaded to the server using FileZilla on PC one, they will appear in the Server and I can access them by logging into the DriveHQ website. So they are definitely there in the folder.”. If you have FileManager on both PCs, why do you use FileZilla? You can manually upload files to DriveHQ using FileManager, or you can automatically sync the folder on Computer 1 with the cloud folder, then FileManager on Computer 2 can sync the cloud folder with the local folder on Computer 2.
If FileManager does not automatically sync the cloud folder with the local folder on Computer 2, please click Help in the menu, then click Event Logs. In the popup dialog, click Send to send the event logs to us. Our engineers will check the logs to locate the problem.