16.04 - caot save 'Netmask' address

I see a strange thing happening. My wifi works in the office but not at home. Actually, the web-based ISP login at home works but I caot open any other page. Tinkering with the wifi settings, I tried automatic but it did not work. Then I found that in manual mode, only the first two digits of the 'Netmask' address is being saved. I have tried several times, with the same result.

I am posting this from the Android tablet and do not see any attachment option. Would have attached a screenshot otherwise. Help will he greatly appreciated.