Our team is using Camunda 7.2 version and we recently migrated 2100+ process instances into new workflow version via custom script as there was no migration feature in community edition. Now we are trying to delete the old deployment that has 2100+ running instances. First we had setup a batch job to delete them after suspending the process definition in cockpit and observed that the batch is deleting 2 to 3 process instances per hour. We are surprised with the performance of this batch and also had to restart the Camunda more than 10 times as it’s getting crashed due to this batch.
Then we realized that this isn’t working as expected, we deleted the batch process and tried to delete the entire deployment via Cockpit. We got multiple “Gateway error” messages and got the below error message in the last try.
We just want a peaceful/simple process to delete the instances from deployment 
Can anyone help us on this please!!
