I always just update through lan but if i should i would just remote desktop into windows. I use teamviewer. But again my mycloud is connected to a host pc.
I myself have been unable to firmware update from the main dashboard page (since the os5 update i think). So i have done it manually from a downloaded firmware file but not sure this option is active for myclouds without a pc connected.
There’s also a way to do it through ssh. Maybe this way is a bit outdated:
Old wd desktop download:
This as well: Download but not sure how it’s supposed to work.
Then there’s the standard option but im sure you have tried this already:
Try another browser maybe or refreshing the page. Portforwarding the modems/routers maybe but it’s not safe to do that on port 80/443 for (standard web browser port) for long i think. There’s Dockers and Entware apps as well.
Well that’s my 2 Cent anyway. 
