At the time of uploading Meter Reading getting standard Error MsgNo EL-128

Hi Experts,

When I was estimating the meter reading through EL-28 transaction I was getting an standard error message as

"Device &1 register &2: estimation could not determine a valid MR" .

Error class:EL

Error msg no:128

Can any one plese explain me the scenario in which we are going to get this error message.

Kindly reply me ASAP.

Thanks in Advance.

Avinash.