my problem is that I cannot access my cloud over internet as in “https://files.mycloud.com/” address I get mycloud device to appear off line even if in my home network everything seems to be OK.
What type of device are you using? Are you trying to open it up with an app or in your browser? If using a browser just place mycloud.com in the address bar.
Go to you MyCloud Dashboard settings, toggle the remote access off then back on. Wait till the connection status indicate something like port forward or relay established then retry accessing https://files.mycloud.com/.