@GaganS 

Check your cable modem logs, by logging into your cable modem, then looking to see if there may be critical 3 or critical 4 error which gives random connection drops due to an unstable signal. 

If that checks out, try swapping the main Deco (wired to modem) with one of the satellite units to see if that may help. If the main Deco loses internet connection or is at fault, the rest of the satellite units will be red as well. Here is how to swap units: https://www.tp-link.com/support/faq/2400/

Other things to try would be to swap the Ethernet cable being used and the LAN port.

@Tony Thanks for the reply.

Checked the cable modem logs. Found some Critical 3. Have included iy below. Please note, I have redacted the MAC address.. Not sure if it was required :)

Also, not sure if  any of these are concerning? 

The last time I had this issue was on 2021-02-19. Do not see any critical logs from that day. I will try to the other suggestion of chaing out the main deco and/or lan cables. 

Is there anything I should watch out for on the deco logs?

2021-02-23, 19:58:05    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-21, 10:18:37    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:12:38    Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:12:28    Critical (3)    No Ranging Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:12:28    Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:12:21    Critical (3)    No Ranging Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:12:19    Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:08:09    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-20, 00:07:36    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-13, 05:26:26    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-11, 15:10:34    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
2021-02-10, 02:27:21    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[REDACTED:40];CMTS-MAC=[REDACTED:6e];CM-QOS=1.1;CM-VER=3.1;
 

@GaganS 

The critical 3 errors are a good place to start. When talking with the ISP some users mentioned having to specify the error to the tech. What can happen is the rep will just see you have "internet" and assume everything is fine.

As far as the Deco you might see longs indicating the WAN being 0.0.0.0 which would give the red LED.