[Q] CM12 Network Issues,Yatse won't find host-XBMC, ES-FileExplorer FTP Server Broken topic

Hello,
a couple of days ago i updated my Galaxy S5 from rooted stock Kitkat (Touchwiz) to Cyanogenmod 12 (nightly 26.01. at the moment, recovery is TWRP).
I know CyanogenMod from using it on my Galaxy S2 already.

unfortunately i keep having some network problems..

At first the phone didn't connect to my Wifi. The Router assigns a fixed ip to the phone's MAC-address. I was able to fix that by configuring the Wifi-conection on the phone to the same IP instead of using DHCP.
Wifi works fine now.

Second: My ES-file-explorer FTP-Server isn't working. It starts well on the phone, but i can't access the IP ftp://192.168.178.xx like i was used to from my windows pc. Also if i ping the ftp://ip-address in the command promt i get a "couldn't find host"-error..

Third: My Yatse XBMC / Kodi remote won't find the Host. it is active in the same network and i can controll it with my girlfriend's stock Galaxy S5, but i can't add the host to my Yatse.. Even if i enter IP and Webserver-Port directly the JSON-RPC check fails..

Any advice?

Thank you very much for your Help!!