WD My Cloud Unable to access device (0)

WD My Cloud Unable to access device (0)

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suddently… today, i cannot access WD my cloud 3T by external network (no matter by my cloud apps or desktop). but can do it by intranet…

however, it was fine in yesterday…

please help… 

There are plenty of threads about this, but I could not figure out why I have the same error every  few days.

It is working for 4-15 days without router/ISP/wdmycloud restart.

Tried with Static IP and DHCP too, tried to reset everything, but nothing seems to work.

Luckily I use it as an external HDD for my router, and forced to use FTP, but next time I will buy a normal NAS, not a cheap one like this.

i have the same problem for a few days