I am a Premiere member and I have set up Emby Server mainly in order to use it with my (several) Kodi installations.
It works just fine with my over 4.000 Movies and 20.000 TV episodes. (Even though setup process took several days in order to get it perfectly working and understand all parts of the Emby Server system)
Now I have tried to setup Emby in my Windows phones and must say that I am extremly disappointed with the "Emby App". It has several huge problems desribed below. Optional there is also Emby Theater but it is mainly intended for use on TV or Home monitors that are bigger so it is not so nice and easy to use on a phone. Emby Theater works and let you login with Emby Connect and it let you play movies without any problems or limitations. However Emby Theather seems less developed than Android App. Final option is using Microsoft Edge internetbrowser which looks nice and is funtional BUT does not let you play any movies (not supported) and it does not let you go fullscreen.
Problems with Emby App:
First problem is that Emby App refuse to login with Emby Connect so I don't get full functions as I should have as a lifetime Premiere member. (More about login problems below). As it is now I can just play one movie per day.
Second problem is that the Emby App for Windows phone is not all all so nice like the same version for Android.
Menus and pictures are oversized and makes it look ugly and difficult to navigate.
It also has problem to handle my big Movie collection and shows simple archive maps instead of nice Movie covers.
(Which is not a problem in the Android version of the same app)
Listing of movies is shown in "List view" instead of Androids nice looking "Cover mode".
Some navigation options are not functioning (bugs). Example going by "Folders" from homepage you cannot open your maps inside there. Touch a map and "nada" happens.
Windows App is also missing the nice and functional menu buttons that you see down in the Andoid version.
(Meaning that you actually cannot do as many thinigs as in Android)
Third problem is that Movie player get stuck on one and the same trailer and refuse to play anything else. So I can not even see my 1 alllowed movie. And I cannot try another movie because of the limitation.
Summary is that the Emby App for Windows Phone needs a major upgrade and as it is for now. Emby Theater is the only working choice for a Windowsphone. To ask people to actually buy the Emby App in Microsoft Store is actually nothing but a robbery. (Pay for such shit - really! Come on it should be free until it has same functionallity as the Android version.
Here follows some details of the problem with Emby Connect and Emby App:
Emby App (not Emby Theater) refuse to login with Emby Connect.
Reading the forums and google around I have tried several things.
Connect with internal end external WIFI network makes no difference. Using the phones 4G also does not work.
Trying with server external address as fixed IP number or dynamic DNS makes no change.
I have used a Windows 10 Phone Lumia 950 XL Dual and a Windows 8 Phone Lumia 920.
Windowsphone 10 version = 10.0.14393.321
Windowsphone 8 version = 8.10.14234.375
I actually also created a second Emby account just in order to try if something was wrong with my account.
But I could not login with Emby Connect from that new account either.
Also I cannot login inside the app with Emby Connect (after login by skip)
P.S. I did upload the logs from my Win 10 Phone.
Pictures are enclosed Windows vs. Android App.
All the Best