You have registered your StreamSets Data Collector to an On-Premise installation of the StreamSets Control Hub and you are unable to access the StreamSets Data Collector UI after upgrading to a new version of Data Collector.
In the above scenario you may see this message in the Control Hub logs:
SECURITY_57 - SDC <SDC_ID> is running SDC version '184.108.40.206', supported version range is ['220.127.116.11', '18.104.22.168']
A user with System Administrator role needs to update the max supported SDC version from the StreamSets Control Hub UI:
Administration -> DataCollectors -> Component Version Range
Set version range to be greater than or equal to the latest version of StreamSets Data Collector you are running (e.g If you are running 3.8.1 you may enter 3.8.10).