In some situations the Web Application Proxy Core component may fail with the Web Application is down error. In this Tutorial we are going over a possible solution for this issue.
One of the reason for this error is when the Web Application Proxy does not communicate with the Active Directory Federation Services on the internal network for a period of 8 (eight) hours.
We can use the cmdlet bellow to check the status of the ADFSTokensigningCertificatePublicKey and if it show obsolete, then the steps that we are about to perform will help on that issue.
The first step is to find out the Thumbprint being used by the Public Certificate that we are using on the Web Application Proxy, we can use the Certificates Snap-in, or the following PowerShell cmdlet.
Having the thumbprint of the certificate, we need to run the following command and our credentials will be required as part of the process.
Install-WebApplicationProxy –FederationServicename <Name> –CertificateThumbPrint <Thumbprint-from-the-previous-step>
The results of the cmdlet are shown in the figure below.
Having success in the previous step, then we can go back to the Web Application Proxy interface and now the service should be up and running.
In this Tutorial we went over a common issue on the Web Application Proxy and a possible solution how to fix it.