How do I resolve the .NET Agent not connecting to the Controller?

[#1]

Symptoms

The .Net Agent is not able to connect to the Controller, due to an incorrect account name and account access keys in the .Net Agent configuration.

Diagnosis

Symptom 1:

The following error message appears when using an SSL connection (port 8181/443):

Controller communication failed. Details: The remote server returned an error: (401) Unauthorized.
Please use certmgr.msc to add Controller Certification Authority certificate to
"Trusted Root Certification Authorities" at computer account (system) level.

NOTE: The SSL error is a red herring. The (401) Unauthorized piece of the message is important.

Symptom 2:

The following error message appears when using a non-SSL connection (port 8090/80):

Controller communication failed. Details: The remote server returned an error: (401) Unauthorized.

Solution

Verify the account credentials in the Controller UI using the following steps (applicable to v4.3):

1. Open AppDynamics Controller UI and log in as an administrator.
2. Click on the gear icon in the top right corner of the Controller UI.
3. Click on License, then Account.
4. Note the value of "Name": it will act as value for Account Name within the Agent Configuration Tool.
5. Note the value of "Access Key": it will act as value for Account Access Key within the Agent Configuration Tool.
6. Click the Save button.