Intermittent internet disconnect

I’m experiencing intermittent internet disconnects that started after my recent plan change. The connection will suddenly drop for about 1 minute at random intervals, then recover normally. This happens across all devices, both Ethernet and Wi-Fi.

Here are my observations and troubleshooting so far:

• The connection cuts out abruptly rather than gradually increasing in latency.
• Pinging 1.1.1.1 and 8.8.8.8. During the disconnect, both suddenly begin returning “Request timed out” for a period of time, without any preceding high-ping spikes.
• At the same time, I can still reach the router/gateway’s local IP normally, so the local connection to the gateway remains up.
• The Xfinity modem status light stays solid white during the disconnect.
• The Xfinity app does show the gateway as offline during the disconnect.
• The issue affects every connected device, including both Ethernet and Wi-Fi.
• Browsers sometimes show “ERR_CONNECTION_CLOSED” or “ERR_CONNECTION_RESET” rather than simply timing out.
• Interestingly, when playing games using P2P hosting, I would remain connected to the other players during the disconnect. Games using a centralized server, however, disconnect immediately.

Modem signal information:

• Downstream power: approximately +4 dBmV
• Downstream SNR: approximately 46 dB
• All downstream channels are locked.
• Upstream power: approximately 40 dBmV.
• The 105, 200, and 297 MHz OFDMA upstream channels are not locked.
• Uncorrectable errors remain at 0.
• I do not see T3/T4 timeouts, ranging failures, or loss-of-sync events in the event log.
• The event log otherwise appears empty, although there are some OneWiFi logs that I’m not sure what they are.

Troubleshooting I have already done:

• Completed the basic troubleshooting steps.
• Replaced the coax cable connected from the utility box.
• Switched back to an older Xfinity gateway/modem that I still had at the time. The disconnects continued, so the issue does not appear to be specific to the original gateway.

I also mentioned the issue during a recent visit to an Xfinity store when I was returning the old modem. I was told that this type of issue can apparently occur after a plan change and that I should contact Xfinity for a reset, although I don't remember exactly what needed to be reset.