@ImtiazAli 

"I can't login to it remotely now."

I'm far away from my home network. 

  @Marteen did you look at More->Internet Connection->IP Address?

That is the WAN address associated with the ISP connection, the external address that may be reacable from outside your network.

I say may be reachable because some ISPs use CG-NAT which will use Network Address Translation (NAT) in a similar way to domestic routers and block incoming connections.

If CG-NAT is being used it will also prevent uPnP from working.

  @ImtiazAli 

I can't connect to any connected devices since I don't know the IP of the deco. I'm far away from the network and need to find out remotely. I find it very weird that the external IP is nowhere to be found in the deco app. 

  @Marteen did you look at "More->Internet Connection" the IP address your ISP has assigned your Deco will be listed under, strangely enough, IP Address!

If you can't connect to that address (you need to be sure it's the ISP not your mistake) then you need to ask your ISP if they use CG-NAT since that will prevent you from connecting remotely. If they do use CG-NAT you should then ask them if they can provide you with an address that is contactable from the Internet.

  @raven-au 

Thank you that actually worked, after a restart it showed my external IP, before it was an internal IP which is strange in it's own way.