While Adding Appdynamics Verification Provider you might get an error and unable to add the verification provider as below:
Invalid argument(s): Task has expired. It wasn't picked up by any delegate or delegate did not have enough time to finish the execution.
Although curl test to Appdynamics controller works fine from the delegate, you may see error in delegate logs as timeout:
Response code: 504, Message: GATEWAY_TIMEOUT, Error:
The reason for this could be most likely the Appdynamics user doesn’t have access to list the Appdynamics application, as after connectivity test we also try to list all the application to validate the user authenticity and it can fail there.
So to confirm if this is causing issue you can run below curl command from delegate:
curl --user user1@customer1:secret https://your_appd_host/controller/rest/applications?output=JSON
You need to pass credentials in below format:
<your_username>@<your_accountname>:<your_password>
So to resolve this issue you need to make sure you are using correct user that has required permission to list all application.