We are unable to open a specific channel, we can see some errors in developer tool console as below:
DX Operational Intelligence 20.x
DX Application Performance Management 20.x
DX AXA 20.x
This problem is related to defect # DE511556
Workflow:
1.Create Email channel from Email page.
2.Create one template from message template page.
3.Email page, Link template what we created on message template page
4.Later delete the template what we have created on message template page.
5.If we open this linked Email channel in Email page it is breaking because we deleted that template on message template page.
Defect fixed in DX 21.3