django SRID conflict between django and mysql

hi,
i have this issue after updating srid on my mysql database from srid 0 to srid 3857
when i save new entry this exception occured

Exception Type: OperationalError
Exception Value: (3643, “The SRID of the geometry does not match the SRID of the column ‘location’. The SRID of the geometry is 0, but the SRID of the column is 3857. Consider changing the SRID of the geometry or the SRID property of the column.”)

how can i fix this issue
and thank you all