@AW4911 

Thanks for reaching out. I understand that your Deco Mesh system is connected to your T-Mobile 5G gateway in Access Point mode, and recently, all your devices lose internet access overnight, even though they remain connected to the Deco network. Power cycling the T-Mobile gateway restores the connection, but you're unsure whether the issue is with the gateway or the Deco system.

Here are some steps you can follow to help identify and resolve the issue:

1. Check the Deco's LED indicators:
• If the Deco units show a solid red light, there may be a problem between your internet provider (ISP) and the main Deco. In this case, please let us know that the main Deco is solid red.
• If any satellite Deco units are flashing red, please mention that as well.
• If all Deco units show green or white lights, proceed to the next steps.

2. Review device settings in the Deco app:
• Go to MORE > Wi-Fi Access Control or Block List and make sure your devices are not being restricted by access control settings.
• Check the Parental Control page to ensure your devices are not included in any parental control profiles that could limit access.
• Navigate to MORE > DHCP Server and confirm that the two DNS server fields (primary and secondary) are empty, as incorrect DNS settings can sometimes cause connectivity issues.
• Go to MORE > VPN > VPN Client and verify that your devices are not listed as VPN clients, which could prevent internet access.

If the issue continues after these checks, it may be related to the T-Mobile gateway itself, especially since power cycling the gateway restores connectivity. You might want to check with your ISP for any known issues or firmware updates for your gateway.

If you need further assistance, please provide additional details such as the Deco LED status during the outage and any error messages you see, and contact TP-Link support for more in-depth troubleshooting.