Hey @ajayshah95,
Welcome to the community and thanks for taking the time to post your issue on the forums.
I’m sorry to hear of the issues that you’re having with your connection on the London Underground.
What device are you using to connect to the underground WiFi network?
Are you using the Connect app to logon to the network, if so, have you tried to remove and re-add the app to your device?
Regards,
Steven_L