Hello Jagar,
For testing purposes, please try connecting in an unsecure mode.
If the connection is successful try using WPA security, but if it’s possible try to select WPA-TKIP or WPA-AES try to avoid any mode on the router which uses both authentications tied at the same time.
If the issues persist, check if there’s a firmware update for your router.
The fact that your ThinkPad successfully connect to another networks eliminated the possibility of a bad integration of the wireless card.
Regards,