Now you ask the customer service of the indian indian tax office why they have an invalid certificate. They are the only ones who know that.
I tried to login https://incometaxindiaefiling.gov.in and got the message as " Invalid Server Certificate ".
Earlier , i.e. , I could log in this very easily , since , last couple of days this message is popped up .
Someone asked me to load java which I did online.
Someone suggested to upgrade I E 8 , which is 6 now I did it also.
However , I can log in to other https sites without any hassle.
I am surprised by this message.