We notice recently when our users open up the Web AVD site and it has the New Client Preview client turned on causing them unable to launch RemoteApp (No issue with Desktop session) at the following ...
TaniaMariscal
Microsoft
MicrosoftWe are sorry you are running into issues. To discuss issues we recommend to share your problem on our Tech Community forum (https://aka.ms/wvdtc) or open a support ticket after you have reviewed the troubleshooting options in our documentation (Windows Virtual Desktop troubleshooting overview - Azure | Microsoft Docs)
We recommend to review our troubleshooting section first. The other option you have is to open a support ticket through the Azure Portal.