2fa enabled on my account – not done by me

hi –
 
I had used my email address goutham.y.kumar@gmail.com to create a login for CAS Swap.  I was trying to access my account and now see that it is asking for 2FA google code.  The same was not enabled by me.  I am not able to access my account.  kindly advise how to reset the same.  I have my username and password intact. 
 
Regards
Goutham Kumar