I have not used iBank (cannot say I have even heard of it) and syncing is something that the TC should be irrelevant to. Any network connection should work.. failure can be due to any number of issues and it is never easy to test where the failure happens.
Also I am still unable to locate my WD My Cloud NAT drive.
This is a straight network issue.
I do not use WD NAS products.. stay right away in fact. They are renowned for issues with Apple systems.
Nevertheless the NAS must be at least available on the network. Please tell me if you can ping it.
Open a terminal and ping the NAS by IP and by name. If both fail, either the setup of the NAS is wrong or the computer is blocked from access to it.
Open the network utilities.
In mavericks apple have moved it and you will need to just search for it..
Do a netstat scan and see if the NAS is available at all.. it probably should be set with the correct setup to keep a static IP. If it will not work by name use IP. It should also be in the same domain as the computers.. domain is local by default but I am seeing issues where the domain is not correct.
Mavericks if you didn't know made a big change to SMB network protocol by default.
It is therefore a big issue where names are like apple names.
As per my instructions in the manual setup.. please try again using all short names in the TC.. very short, less than 10 characters please. No spaces and pure alphanumeric.
Mount the NAS manually using the name with domain..
Try using SMB1 as I hear SMB2 is buggy.
So if SMB://WDNAS.local OR SMB://WDIPaddress eg SMB://10.0.1.100 (replace with the actual IP and WDNAS replace with the actual network name of the NAS).
Replace SMB with CIFS
I am not sure if WD MyCloud can handle AFP but you could also try changing SMB with AFP.