There is not necessarily any size limit, and 86kb is very small and the Fax Server should be able to handle it efficiently. What kind of fax hardware are you using? If you are using the fax modem that comes preinstalled on a computer, this is most likely the issue. Preinstalled modems have no hardware basis at all, causing them to be low quality and not powerful enough to handle the functions that Fax Server demands on it. It is highly recommended you purchase an external usb fax modem.If you are using an external usb fax modem, or a PCI fax modem, try updating your drivers and do any kind of diagnostics possible to determine if your hardware is faulty.