Looking at then JIRA CircleCI plugin, it looks like it only works for JIRA Cloud and JIRA Server 7.2.1 - 7.2.15
Our sandbox is at 8.2.3 and production is at 7.7.1. Due to this issue, plugin doesn't work for us.
In addition, it looks like Circle CI has stopped supporting the Jira Server version all together. The Cloud version of the plugin was released in May 2019, but the Jira server version has not been updated since September of 2016.