After following several posts and tutorials on properly fixing IIS dynamic compression for JSON responses, i used to be still reaching a dead finish. For no matter reason, my responses were still uncompressed. Apparently, using the NetworkService account doesn’t perpetually play nicely with static or dynamic content compression.

The NetworkService account doesn’t have permission to the IIS Temporary Compressed Files folder, preventing it from writing and reading out compressed streams. The best thanks to get around this can be by adding the NetworkService account to the IIS_IUSRS group (which already has permissions to the IIS temporary folder).

1. First step, Open the local Users and groups management console.

2. Next, Select Groups from the sidebar.

3. Now, open the IIS_IUSRS property window.

4. Click Add, then enter Network Service as the user. Make sure to have your nearby workstation as the area, then Check Names to make certain you entered everything effectively. Click OK.

5. Next, Click OK on the IIS_IUSRS property window.

6. Close the Local Users and Groups management console
7. Restart IIS

Dynamic compression should be working now!