Attestation mail events are not getting triggered


We are working on One IM version 8.0 and we have restored our database. But, now attestation mails are not getting triggered. We see that event "DecisionRequired" should get triggered when a new attestation is raised or when a new ITshop request is raised. In case of ITshop request, this event is getting triggered but not in case of Attestation case. We have checked the configuration parameters and mail configuration parameters for attestation are enabled. What can be the cause? And how to resolve this?