Time Machine couldn’t complete the backup to “WDMyCloudRiyadh.local”

Can anyone help me in resolving the error appearing while automatic backup of MACBook data on WDMY Cloud, Time Machine. The error started when I installed MacOS Mojave (10.14.2) 18C54. Please see the screenshots. I followed clicking “Start Backup Now”, after some time screenshots 1 and 2 appears. Every time, the long sequence of alphabetical and numerical numbers appearing file location is different (screenshoot 2), don’t know is this having some relevance with the error or not.

Screenshot 119%20PM
Screenshot 2

Once I succeeded in locating the file and changed file name of Pro.sparsebundle. However, after finishing a new backup, same error appear. Means whenever a backup is finished, I have to change the file name to create a new backup.

I will appreciate your help in providing a permanent stepwise solution