Approval not getting added on submit of change

Hi, Change in SM 9.52 is configured using process designer. All approvers and phase transition was working fine. But suddenly Approval record generation has got corrupted and whenever i submit a new change i get the below error. Any one has any suggestions on solving the same. Kindly do suggest scdb - 15: The record being updated contains all NULL keys (approval.generate,build.all.status) file:(Approval) key:(unique.key=,file.name=,name=,component=) (approval.generate,build.all.status) scdb - 14: The record being updated contains a NULL key (approval.generate,update.record) file:(Approval) key:(unique.key=,file.name=,name=,component=) (approval.generate,update.record) scsql - 100: Key #1 is empty. (approval.generate,update.record) The Change you scheduled conflicts with the existing freeze period or maintenance period. Change "C030135" added. Change C030135 Phase Immediate Supervisor Approval Opened by falcon.