According to the Cisco AppDynamics Professional Implementer (CAPI) documents, the two reasons for the missing correlated server-side snapshots are:

Server has set the HttpOnly flag on all cookies. (A) This is a valid reason because the HttpOnly flag is a security feature that prevents client-side scripts from accessing the cookies. However, the AppDynamics JavaScript Agent relies on the cookies to correlate the browser snapshots with the server-side snapshots. The JavaScript Agent injects a cookie named _appdyn_browser into the browser requests, which contains the correlation information. If the server sets the HttpOnly flag on all cookies, including the _appdyn_browser cookie, the JavaScript Agent cannot read or modify the cookie, and the correlation fails. To enable the correlation, the server should not set the HttpOnly flag on the _appdyn_browser cookie12.

Server-side application is not instrumented with server agent. (E) This is a valid reason because the server-side snapshots are collected by the AppDynamics app agents that instrument the application servers. The app agents monitor the business transactions that are executed by the server-side application, and capture the execution context, call graphs, errors, and metrics. If the server-side application is not instrumented with the app agent, the server-side snapshots are not available, and the correlation fails. To enable the correlation, the server-side application should be instrumented with the app agent that is compatible with the application server and the Controller34.

The incorrect options are:

Correlated server-side snapshots work only for .NET Applications. (B) This is not a valid reason because the correlated server-side snapshots work for any application server that is instrumented with the AppDynamics app agent, not only for .NET applications. The AppDynamics platform supports various application servers, such as Java, .NET, PHP, Node.js, Python, and C/C++. The app agents collect the server-side snapshots for the business transactions that are executed by the application server, regardless of the programming language or framework34.

Correlated snapshots are visible only if the injection mechanism is Automatic. © This is not a valid reason because the correlated snapshots are visible regardless of the injection mechanism. The injection mechanism refers to the way the AppDynamics JavaScript Agent is inserted into the web pages. There are two injection mechanisms: Automatic and Manual. The Automatic injection mechanism uses the app agent to inject the JavaScript Agent into the web pages that are served by the application server. The Manual injection mechanism requires the user to manually insert the JavaScript Agent into the web pages. Both injection mechanisms support the correlation of the browser snapshots and the server-side snapshots, as long as the JavaScript Agent and the app agent are configured correctly .

Correlated snapshots are visible only if browser is Chrome. (D) This is not a valid reason because the correlated snapshots are visible regardless of the browser. The AppDynamics JavaScript Agent supports various browsers, such as Chrome, Firefox, Safari, Edge, and Internet Explorer. The JavaScript Agent collects the browser snapshots for the web pages that are loaded by the browser, and correlates them with the server-side snapshots, regardless of the browser type or version .

Correlated server-side snapshots are visible only if Java version is 1.7+. (F) This is not a valid reason because the correlated server-side snapshots are visible regardless of the Java version. The AppDynamics Java Agent supports various Java versions, such as 1.5, 1.6, 1.7, 1.8, and 11. The Java Agent collects the server-side snapshots for the business transactions that are executed by the Java application server, and correlates them with the browser snapshots, regardless of the Java version or vendor .

References:

1: Browser Snapshots - AppDynamics

2: Troubleshoot Browser RUM - AppDynamics

3: Transaction Snapshots - AppDynamics

4: Supported Environments and Versions - AppDynamics

[5]: Browser Real User Monitoring - AppDynamics

[6]: Set Up and Configure Web EUM - AppDynamics

[7]: Browser Support - AppDynamics

[8]: Java Agent - AppDynamics

[9]: Java Supported Environments - AppDynamics