Tamil Nadu Electricity Board [TNEB] — not able to add consumer number

Address:

600073

I have tried multiple times to add consumer number in TNEB site. But i'm able to add so.

I have cross verified with my EB card as well. I have given correct region and consumer no.
Still I get same error again and again.

The account is active too, still i'm not able to add consumer number. It says 'invalid consumer no'

Please help in resolving this problem.