Do you reboot your modem regularly? Try that first.
Also there is a known weakness of this modem. I suspect you could be getting interference. Perhaps someone new moved to your area and now there is more wifi signals around you competing with the Fizz modem. If the issue persists, you have 2 options.
1. Use ethernet wired connection.
2. Put the modem in bridge mode and use your own router.
Hope this helps. Good luck!
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