If you need to reset your My Cloud you can do either a 4 second reset or a 40 second reset. See the following WD Knowledgebase article on how to reset a My Cloud device. Either method should not affect any user data on the drive.
With WD terminating OS3 support it is possible using the MyCloud.com web portal to setup or access a My Cloud device may no longer work. One can use the My Cloud Dashboard to setup their My Cloud instead. See the following WD Kowledgebase article on how to setup a My Cloud using the My Cloud Dashboard.
One can access their local network My Cloud using Windows File Explorer or Mac Finder or using a third party file manager app on their mobile device. One can still map a My Cloud Share for easier access in Windows or Mac OS.