Hi guys,
I installed Owncloud on my PC and I configured the remote access with a DDNS service (hopper.pw). The problem is that I cannot connect to Owncloud using that DDNS domain when I am in LAN, but I have to use the PC's local IP.
Having to change the URL every time, depending on where I am (at home or not) could bed very frustrating, especially with a smart phone.

Do you know any way to solve this problem, being able to use a unique URL to connect to my server, irrespective of my position?

Thank you very much

Sounds like your router doesn't like it when its external (WAN) interface is accessed from your internal network... You may need to check your router's firewall settings. Most routers see an internal IP (e.g. your smartphone on your home network with a 192.168.x.y class C private address) connecting to your router's external interface (whatever your current DHCP WAN IP is) and think that it is a IP spoofing attempt. That's technically correct, since you should never, ever see class C private IP addresses (i.e. 192.168.x.y) on your public/WAN/Internet router interface. Having said that, with proper router setups this should still work, but like I said, most routers botch that. Anyway, that's just my guess.

Can you ping your hopper.pw address from your home network? Perhaps it's only port forwarding that doesn't work, but basic ping does?

You need a local DNS to resolve your domain name to the local ip.

Something like dnsmasq is ideal.