Ios iphone not connecting to local network

When I’m on my local wifi network, my iphone says "Drive offline WDMyCloud is not accessible. If I disconnect from wifi, I’m able to get a remote connection through cellular. This has been eating up my data plan.

Any ideas?
Doug

Sounds like a local router issue to me.
What router make and model? Have you checked your routers firewall or security settings?
Have you connected your mobile phone to a different WiFi (IE: Remote WiFi) connection like your neighbors/friends/office or something like that to check connection?