My rebooting effort from yesterday remains successful so far today.(fingers crossed)

Just in case it makes a difference, after reverting to 5.4.7 for the OC200 and 3.20.2 for the SG2210, I have not installed the latest versions of either firmware as I am trying to stabilize everything and then add the latest versions (5.5.7 & 3.20.4) back again.

Since downgrading both devices did not help with the issues, I don't believe those upgrades are the issue but want to be clear on my status, in case some of you have remained at the latest firmware versions and try rebooting everything without success.

If rebooting ends up being the solution for everyone, it points to the potential need to reboot all devices, every time a firmware upgrade is done to any device. Kind of a PITA, but given the potential alternative, not too bad.

Anyway, if this works out, I'll update my SG2210 to 3.20.4, reboot, and wait a while. Then, update my OC200 to 5.5.7, reboot, and wait a while.

  @Fleegle61 

That's great!!  Glad this worked out.

I'll probably update the OC200 tomorrow and wait at least a few hours to update the 2210P.

Dear @lflorack, @Fleegle61,

Thank you for taking the time to post the issue in TP-Link Community!

The issue has been reported to the support engineers for further investigation. If convenient, could you please help to provide your network diagram for checking? Are you both using the TL-SG2210P v3.20 as the main switch in the network?

Hi @Fae 

I've pasted my LAN diagram below.  Yes, the TL-SG2210P is my main switch.

As noted in this thread, the system had become increasingly unstable over the past few days, but after I upgraded the firmware for both the OC200 (5.5.7) and the SG2210P (3.20.4) on the same day, all of the system hardware (all Omada) was almost continually going through disconnect/reconnect/readopt loops from the OC200 controller at an increasing rate.  I tried downgrading the firmware for the OC200 (5.4.7) and the SG2210P (3.20.2) without any improvement.  I rebooted the OC200 and SG2210P individually without improvement.  I tried a few other things also without success.  Finally, I rebooted all of the Omada devices simultaneously and everything came back up and is now completely stable again and has been so for about 20 hours at this point.  As I mentioned earlier in this thread, at no time during all of this did any of my 39-42 connected clients lose connection to the LAN or the internet.

A similar discussion to this one has also been taking place on Reddit with 5-10 others - all with the same issue.  While all of them have the OC200 and some have the SG2210P too, don't know that all of them do.  Rebooting everything simultaneously seems to have solved the issues for everyone who has reported back to the thread.

I will upgrade the OC200 and SG2210P back to the newest firmware versions (5.5.7 & 3.20.4) today or tomorrow to see if the network remains stable.  I anticipate doing a full hardware reboot after each firmware change to avoid any similar issues.