Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
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- Open an incognito tab/private browsing tab and paste the link below-
https://setup.office.com/redeem/enter-key
Click 'Get Started' and type your 25-character product key.
Then sign in with your Microsoft account and click Next to add your product to your account.
If you are still having trouble,
- Use another browser or connect your PC to a different Wi-Fi network, such as a mobile hotspot, and see if you can redeem the key.
- Alternatively, try clearing your browsing History, cache, and cookies.
If you are still having issues, let me know.