User's email address always disappears

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX2
1

The user’s email address on my MyCloudEX2 always disappears a few days after I have set it. Hence I couldn’t log in to MyCloud from outside.

Device firmware is 2.30.196

I do have another MyCloud, white color, single bay. It never has such an issue.

Anyone know what is happening on my MyCloudEX2?

Thanks in advance.