Locked out of MyCloud

I have been using WDMyCloud as a personal cloud storage/file server for some time. For convenience I have mapped several directories as Windows 10 network locations. This not only gives me quick access to files, but enables me to have off-site (i.e. an external building on the same network) backups running from here using the mappings as source or destination.

I have just returned from holiday. Before going I shut down all IT. On restarting I find that my Fritz!Box is not seeing the WDMyCloud as a connected drive. I tried to re-add it, but it said that the address is not available, suggesting to me that I hae something misconfigured, locking me out. I have tried every workaround I could think of, including giving the reserved address to Firefox browser, but to no avail. Windows network troubleshooter says that my configuration is correct but the device is not answering. Can someone please suggest how I can proceed? Thanks.

What are the LED’s on the front and back of your My Cloud doing? Have you tried a reboot of your router?

The front has a steady blue led next to the power symbol. Behind, against the network port, there are two leds. The bottom one is yellowish and steady, and the top one is green an flickering as though passing data. Yes, I’ve tried rebooting the router.

SOLVED!
I had accidentally switched on Guest Access. Removing that is allowing normal access to my files. Thanks for your time and trouble.