@JonKong 

When enabling the guest network you need to disable one wireless band, so only have the 2.4G enabled, not both. The Ring device will keep jumping back and forth networks causing the drop.

@Tony sorry I should have explained, I did set to only 2.4Ghz but it still keeps disconnecting.

Ring sent me a replacement, which does exactly the same thing. I have sent up an automation to notify when it connects and disconnects. It's about every 2 to 3 minutes.

Attached is the history for this evening.

@JonKong 

If disconnections keep happening on a single band you can try swapping the main Deco with another to see if that is the culprit. If disconnects continue, I would recommend following up with support.

@Tony thank you for your reply. I have swapped my main Deco for one of the others, the disconnecting it still happening constantly.

@JonKong Have you had any luck fixing this, as I have exactly the same issue.  Only recently bought the M5 Mesh System, and with notifications turned on mine is also connecting and disconnecting frequently (ever few minutes). I have done all of the things suggested, guest network, turn off 5Ghz, turn off beamforming, and fast roaming.....

@Maver1ck74 no I haven't, my only solution was to dig out my old TP-LINK router and plug it into one of my M5s. I've set up a new 2.4ghz network and connected my Ring to that.  TP-Link haven't offered any working solutions for the M5 and Ring.

@JonKong Real shame TP-Link and Ring aren't working together to resolve this. Have now setup a old Dlink Router as an access point, and seems to be working better. Thanks for the advice

I have same issue. Just got the M5 the other day withe premise that it would support Ring better than the previous 2 Netgear routers that I've tried. Based on scouting the web on the subject, it sounds like a Ring issue. A lot of ppl out there are having this same issue where Ring is flooding their wifi network, regardless of the router type. I'm grateful that you've shared your solution of separating your network and placing Ring on a different one. I will try it. Thank you!

Just to add my solution... I had a problem setting up my Ring doorbell to my TP Link. I narrowed it down to the Ring doorbell not supporting the mesh system. I ended up getting a NetGear wifi extender and hardwiring it to my TP Link Router. From there I simply set a password on the wifi extender by typing the IP Address into a web browser and then setting up my Ring doorbell using using the network created by the wifi extender. Hope the helps someone. 

  @JonKong 

so I have a similar though not exact issue.   Mine disconnects maybe once or twice daily...I'm using Deco Mesh specifically for the ring and only my phone and laptop use that network...nothing select. I did that specifically so it would have dedicated and strong wifi connectivity.  But I also set up alerts and it seems like once or twice a day or every few days at minimum, that I get the notice that "my simple link" has disconnected and then my ring device has disconnected.  Without a minute or two they both Re-connect on their own...but I just don't get why they disconnect at all.  There seems to be no indications of any problems with the Deco Mesh set up that I can see