Configuring a static IP like f.e. 217.62.144.196/30, i.e. net: 217.62.144.196 1st: .197 (router), 2nd: .198, bc: .199 is not possible in GUI.
GUI only presents masks of 255.0.0.0, 255.255.0.0, 255.255.255.0, but these are only the CLASS A,B,C centric masks, not the mask that is essentialy here.
You have to configure it CLI with ip or ipconfig. Be aware of your route here; it has to be your configured router address - route add etc.
When doing it this way the GUI shows still the wrong mask, f.e. /24 or /16.
Please, be correct here and please, precalculate the correct broadcast address for the used subnet.