Android Studio Updated but Unable to Install Any Plugins

I recently updated Android Studio to the latest version, and since the update I am unable to install any plugins from the Marketplace or from disk. Every attempt results in an error saying the plugin cannot be installed or downloaded.

Here is what I have already checked:

• My internet connection is working normally

• Firewall settings are fully open for Android Studio

• Proxy settings are configured correctly and match Android’s recommended configuration

• I also tested the same process on my MacBook, and I get the exact same error

• I tried restarting Android Studio, invalidating caches, and reinstalling plugins manually — nothing works

• The issue started only after updating Android Studio

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It seems like Android Studio is unable to reach the plugin repository even though the network is fine.

Question: What could be causing Android Studio (on both Windows and macOS) to fail when installing plugins after an update, and what steps can I take to fix this?