What My Cloud model are you running? Single bay or multi bay?
If you are running the newer generation v2.x single bay models then, you can download the firmware file manually and update manually. See the WD Support Software and Firmware Downloads page which allows one to download the firmware for their My Cloud (all models):
http://support.wdc.com/downloads.aspx
Or see the single bay firmware 2.21.119 discussion thread which has a direct link to the latest v2.x single bay My Cloud firmware.
https://community.wd.com/t/firmware-2-21-119-9-20-2016-discussion/178944
