This means the TIMESTAMP stored in your BigQuery table has the numerical value 6328502092800000000.
This numerical value is intended to represent the number of micro-seconds since the start of the Unix epoch (1st Jan 1970, 00:00). If you do the calculation, this is a date over 200,000 years in the future; the error message is telling you that dates from the year 10,000 A.D. onwards are not considered valid.
Looking at your value, it seems likely to me that something has gone awry and you are actually representing nanoseconds since the start of some epoch - the unmodified value should not have been uploaded to BigQuery as a TIMESTAMP. This may be the fault of the client library which you are using to upload data to BigQuery, or of the code that passes data to it.
If we simply assume your value is 'nanoseconds since the start of the Unix epoch', we get a timestamp on 17th Jul 2170 - possibly what you wanted, if you were expecting dates in the future to be stored. Alternatively it may be that we have the wrong epoch (in other words, perhaps you are counting nanoseconds from a different starting point?). In that case you would need to determine the correct epoch (it depends where the data came from!).