Tasks and events pane is blank/ empty

Hi

Several of my virtual machines have an empty tasks and events pane. I use vcsa, there is enough space in /storage/db. The size of the vcenter server db is appropriate to the number of hosts and vms. I've reduced the retention period but there is no immediate effect. What could be the problem? What is the fix and how can I instantiate the tasks and events immedietly?

Please let me know for additional info.

Thanks