First, see the dedicated subforum for the My Cloud EX2:
http://wdstagingsplit.staged-by-discourse.com/c/network-attached-storage/wd-my-cloud-ex2
This subforum (My Cloud) is generally for the single bay/single drive My Cloud units.
Also see the following post that discusses various thing to check in Windows 10 that may be preventing My Cloud access. Specifically see Windows 10 Specific Method 1 through Windows 10 Specific Method 5 for suggestions to try.