Ex7000 as AccessPoint gives Netgear login pop and all domains resolves to 192.168.1.250

Hi Everyone, 

I have a EX7000 extender. Using it as AccessPoint. Below are the issues. 

1. Computers connected to the WIFI gets right IP from the router. But All domains resolved to 192.168.1.250 ,when i set it on dynamic IP. My office lan is 192.168.0.0

$ ping google.com
PING google.com (192.168.1.250): 56 data bytes
Request timeout for icmp_seq 0

2. When i use static IP mode. Lets say i assisnt IP 192.168.0.250 to the router. Devices when connected to the Extender, gives a pop up from Netgear for login. How to disable this POP. THe netgear genie portal does not have any option to disable or enable this. 

3. When i enable 2.4ghz frequency the router in my office the router freezes. Keeps restarting without giving me access both on lan and wifi. This happens only in my office. If I move away from the building no issue. I assume this is a frequency conflict. Though i am not sure. whats the casue. How to resolve this. I have other devices working fine in the same frequency.