15 December 2018
This type of error shown when the paid challan is either not reflecting online or details of challan have not been mentioned properly in the return template.
Check the Challan details in the return and also check the challan online after login into mahagst.gov.in -- select payment -- select pending transaction history. you cal see your challan paid history over there and check your status from there, if status is "pending" then click there to complete the challan sync process and then file the return.
If still problem exists then contact to your nodal officer or customer support of Mahagst for solution.