Diagnostics tab causing error

In the web UI for v2.6.0.778, when I click on Configuration > Diagnostics, it fails with the following error:

Unable to find a constructor to use for type System.DelegateSerializationHolder+DelegateEntry. A class should either have a default constructor, one constructor with arguments or a constructor marked with the JsonConstructor attribute. Path ‘Octopus.Platform.Deployment.Guidance.Guided.DispatchedItems.443dc094-9c55-11e4-80c7-00155d960d09.ActivityIdTracker.Delegate’, line 1, position 4893.

Is this a known error? Any fixes or workarounds?

Got the same error, but only while a Tentacle is stuck. Soon as I cancel the job, the diagnostics page works again.

Hi Folks,

Thanks for this report! It is now a known issue. I’ve created a GitHub issue that you can track here:

As Johann has stated, it appears to be linked to tentacle tasks and should be viewable when tasks are not running?
Please share any information here or in the ticket as you find it.