SCENARIO :
There’s no history record for GST Tax Return but not allowed to amend transaction (Original transaction date was locked by non-taxable period.)
SOLUTION :
1. Run script to check in Management tools
select * from SYSTEMDATA
where systemdatacode = 'OldGSTValidPostingDate'
or systemdatacode = 'GSTValidPostingDate'
*Result showing there’s some previous record
2. Run script to clear it
Delete from SYSTEMDATA
where systemdatacode = 'OldGSTValidPostingDate'
or systemdatacode = 'GSTValidPostingDate'
DONE
Refer attachment for details