Slowness in web applications might be result of a wide range of underlying issues in the application code, client side, network or web server. Therefore, system administrators should analyze IIS logs, Failed Request Tracing logs, dump files, and HTTP.SYS logs to narrow down the issue.
IIS
Nuget package for System.Net.Http on .NET Framework 4.7.2 and newer versions
If your web application has dependency on the System.Net.Http Nuget package, it may break after you upgrade .NET Framework version to 4.7.2 or a newer version. This issue occurs if you are using Visual Studio 15.5 or a higher version.
w3wp.exe is Suspended after dump collection
After collecting a dump file by using DebugDiag, you may see w3wp.exe process Suspended in the Resource Monitor. This is a known issue with the new version of DebugDiag and it’s a UI problem. The process is actually functional (IIS is able to server websites).
BadImageFormatException: Bad method token
If you are using AppDynamics version 4.5.17 or lower and receiving “BadImageFormatException: Bad method token” error while trying to access your application hosted on IIS, please update your AppDynamics to mitigate a known issue.
The missing Server Hello in TLS handshake (ERR_SSL_PROTOCOL_ERROR)
For TLS communication to be successful, a client machine makes a request to IIS server over TLS by sending Client Hello package first. Then the server is supposed to respond it with Server Hello package. What if the server is not sending Server Hello package?