Hi, 

the Atlassian Jira Software Cloud plugin has stopped working properly for some time now. 

I am using the latest version of Jenkins 2.454 and the latest Atlassian Jira Software Cloud 2.0.14 plugin.
When trying to establish a connection to Jira Cloud, I get the following message:
Error message from Jira: JWT verification failed. Please make sure you configured the same secret in Jenkins and Jira

I enter the correct Site Name, Webhook URL, and secret
Sometimes the attempt will pass, a case of 1 in 100. 
I have installed different versions of the plugins and different versions of Jenkins. It happened that everything worked correctly for a while and then no longer.

I have verified with the developer tools the network traffic when clicking "Test settings" - every time the response code is 200, the connection has been established. Despite this, for some reason I cannot establish a permanent connection.

I tried installing Jenkins on computers and virtual machines connected into the company domain.