Hi @Quang Anh Nông,
I tested the "Install this site as an app" feature in Edge on my own device. Everything worked fine here and the issue you mentioned did not occur. Firstly, I suggest that you can try some basic Troubleshooting to see if the feature can work:
- You can try to clear your browser data and reapply this feature.
- You can also try to install other sites to see if the same error occurs.
In addition, you can use the "WebAppInstallForceList" policy to force Install a site as an app. Please note that this policy does not allow users to uninstall or turn off installed apps.
If the above solutions still don't make this feature work, I suggest you should press "Alt+Shift+I" to submit feedback in Edge.
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Best regards,
Jinxin Wang