While updating a Series 5000 Card through SmartUpdate in APPoloGUI, the above mentioned error may occur.
This error is mostly caused by a newer APPoloGUI and older APPoloControlServer Version.
For example if you are using APPoloGUI Version 8.8.6 with APPoloControlServer 8.8.1.
In this case, please update the APPoloControlServer to 8.8.5 OR update both APPoloGUI and APPoloControlServer to the latest released Version and run updates again.
While using older versions of APPoloGUI and APPoloControlServer , updating Series 5000 Cards where the newer Firmware file has a size >= 2 MB, the update may fail with the same error.
The reason is, older server version can upload only files < 2 MB.
In this case, please update the APPoloGUI and APPoloControlServer to the latest released Versions and run updates again.