Installing AppDynamics causing 404 response for every call. (.Net Web API)

[CommunityUser]

I have installed AppDynamics in my windows environment to monitor my application (asp.net web api). I configured appdynamics and confirmed that it is sending data to the AppDynamics controller. However, after installing appDynamics I always get a 404 response for my web application (note: it works as expected before install and after uninstall). We did an iisreset after installation and configuration to no avail.

This is the only block of useful entries I found in the AgentLog, but haven't been able to track down what is happening:

2015-04-30 16:36:09.8855 6056 w3wp 2 8 Info RequestReflector Could not get field HttpRequest._BufferlessInputStream even though .NET 4 or above
2015-04-30 16:36:09.9480 6056 w3wp 2 8 Info TopBackendsProcessor Started TopBackendsProcessor to process every [100] ms
2015-04-30 16:36:09.9480 6056 w3wp 2 8 Info TopBackendsProcessor Started TopBackendsReporter to report every [5] mins
2015-04-30 16:36:12.5887 6056 w3wp 2 8 Info BusinessTransactionRegistry Sending transactions to register [BusinessTransaction{id=0, name=, entryPointType=ASP_DOTNET, internalName=/api/user, componentId=26591 ,applicationId=0, applicationComponentName=, matchCriteria=MatchCriteria{matchRule=, namingConfig=DiscoveryNamingConfig{namingSchemeType='uri', properties=[Name:uri-length, Value:first-n-segments, Name:segment-length, Value:2]}}, createdOn=1/1/0001 12:00:00 AM, background=False, analyticsDataCollectionEnabled=False, configuration=, createdNodeId=0, enabledForEUM=False, eumAutoEnablePossible=}]
2015-04-30 16:36:12.6824 6056 w3wp 2 8 Info BusinessTransactionRegistry Registered BT Name[/api/user], Id[86864]
2015-04-30 16:36:46.5115 3196 w3wp 2 10 Warn AgentCommunicator could not connect to named pipe: 2
2015-04-30 16:36:46.5115 3196 w3wp 2 10 Info MetricPoller GetPerformanceCounterValues failed
2015-04-30 16:36:57.6055 6056 w3wp 2 10 Warn AgentCommunicator could not connect to named pipe: 2
2015-04-30 16:36:57.6055 6056 w3wp 2 10 Info MetricPoller GetPerformanceCounterValues failed
2015-04-30 16:37:51.9813 3196 w3wp 2 14 Warn AgentCommunicator could not connect to named pipe: 2
2015-04-30 16:37:51.9813 3196 w3wp 2 14 Info MetricPoller GetPerformanceCounterValues failed
2015-04-30 16:38:03.0752 6056 w3wp 2 10 Warn AgentCommunicator could not connect to named pipe: 2
2015-04-30 16:38:03.0752 6056 w3wp 2 10 Info MetricPoller GetPerformanceCounterValues failed

With how easy this seems to install I'm sure it's some quirk with my Application, but I'm not sure where to look. Has anybody seen this? Any more ideas of where to look or possible misconfigurations?

Thanks in advance for any help.

[Venu_Babu_Thang]

Hi,

Is this issue happens only for a specific page or for all the screens in the application?  Did you notice any errors/warnings in the Winodws Event Viewer logs related to this issue?

Thanks,

Venu.