How to tackle this problem of signing into wifi network? When I connect to WiFi networks, it comes up with a notification to 'Sign into WiFi network.' Is it a permanent problem? If not please let me know what is the solution?
This occurs when the Wi-Fi network is a captive portal. The network lets you connect to it, but it redirects all web traffic to the Wi-Fi network's own page - typically a login page, or a form to accept some terms and conditions before you can use the network.
When you click the notification, the phone will open a browser to let you sign into the network. Once you've done this, the network will stop redirecting your web traffic, you'll be able to use the internet as normal, and the notification will go away.
If you can't do this (you don't want to accept the terms, or you don't have an account to sign in with on this network), you should "forget" the network in the Wi-Fi settings, so that the phone won't bother connecting to it again.