Page not loading when multiple tabs are open

Hi Radzen team,

Our team is seeing this issue where if we open a few links then the pages does not load. As you can see the 3rd tab is the last opened one and it doesn't load.

these tabs were opened by clicking the link in the datagrid column Id.

It's not happening if I run it locally. It happens in our QA system where multiple people are using the application.

Your server needs more resources most probably. Check also the browser console for errors.

If we close any already opened tabs while the page is loading , the data loads in this page. If we wait a few seconds this is the error that shows up . It shows up around the 4th link that's clicked.

eg: I click the 1st id from the Organization page, the linked page opens, I go back to Org page and click id 2, page opens, same happens for 3rd link too. When I click the 4th link, the page shows the blank page. If I close any of the previously opened pages the 4th page loads. Otherwise the error above is seen.

See my previous reply. Your server needs more resources most probably.

@enchev, what is the recommended system configuration for Radzen application?

This is not related to Radzen at all. Radzen generates normal Blazor applications and I suggest you to check official Microsoft documentation for more info:

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This sounds a lot as this Blazor issue: [Blazor server side] Cannot open site more than ~10 times at the same time when deployed to IIS · Issue #17907 · dotnet/aspnetcore · GitHub

It links to the SignalR documentation which states the following:

Note that if a client operating system is used, such as for development (Windows 8 or Windows 7), full versions of IIS or Cassini should not be used, since there will be a limit of 10 simultaneous connections imposed, which will be reached very quickly since connections are transient, frequently re-established, and are not disposed immediately upon no longer being used.

In short IIS has a limit of 10 simultaneous connections when running on a client version of Windows (as opposed to server).

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Wanted to give the solution here that worked for me to open multiple tabs (more than 5) in IIS in Windows server if it will help somebody who faces the same issue.

"Blazor works best when using WebSockets as the SignalR transport due to lower latency, reliability, and security. Long Polling is used by SignalR when WebSockets isn't available or when the app is explicitly configured to use Long Polling." - From

Enabling Web Sockets as follows resolved my issue.

  1. Open Server Manager
  2. Open Add Roles and Features
  3. Expand WebServer (IIS)
  4. Expand Application Development
  5. Select WebSocket Protocol