I'm in the same boat, my second one just failed after a brief power outage, switch was behind a surge protector. It lasted about 2.5 months. The one before that also lasted about 2.5 months. 

Support basicaly just went the replacement route immediately, implying that whatever the issue is, is some sort of hardware problem that cant be remedied by software. 

IDK If I can even get a refund from the distributor i bought it from at this point so I'm stuck in this cycle. Also the options for 2.5GBE are limited, especially with PoE+ support. 

  @vGeek79

This is absolutely not a "business-grade" product. I emailed TP-Link, not that I am expecting much, I'd at the very least appreciate if they could elaborate on what is happening and what they're planning to do to fix it. I bought their Wi-fi AP that is POE+ and 2.5G, I don't think they have another product that does all that in a 10 port switch. Does any one know of any cases where this is happening on the larger switches like the TL-SG3428XMP?

  @vGeek79 

Just RMA'd my second TL-SG3210XHP-M2. First one died December 7, 2021 so with Christmas break and global shipping delays we didn't get a replacement (under warranty) until January 31, 2020!

Second one failed last Friday afternoon (13/05/2020) so only three and a half months of service.

First I noticed one of our EAP660HDs had lost connectivity. I noticed the port it was connected to on the TL-SG3210XHP-M2 had POE power but no link lights. Testing the EAP in various scenarios and reseting to factory didn't bring the EAP back to life so I opened a support ticket with TP-Link for the EAP (that was on the 12/05/2020).

The next day the switch started spitting out the below messages on the serial console:

1/0/1, PHY FW RELOAD.
1/0/1, PHY RESET.

So I rebooted the switch in the hopes that I might clear the port state. On reboot all the 2.5GB ports failed!

I tried various tricks with firmware versions that other community members in this thread have tried but nothing will bring back the dead 2.5GB ports. The SFP+ Ports both function normally, BTW.

I got onto TP-Link Support again and they more or less RMA'd it immediately. Then (quite confusingly and somewhat unprofessionally in my mind) they swapped the open ticket for the EAP to cover the switch instead!

I've since had another EAP fail. Not sure if it was related to the dying switch ports but now I have to open another case with TP-Link support for the two dead EAPs.

The remaining two EAPs have been powered up with the power adaptors. I configured a TP-Link SG108E with VLAN trunks to handle the WiFi SSIDs and the Omada controller software picked up both the live units. At least we have some limited coverage while all the hardware is RMA'd! And I will give a little credit to TP-Link for making the Omada controller software resilient enough to pick up the live EAPs through a low end switch.

  @vGeek79 Surprisingly, TP-Link already responded to my email. However, they claim that firmware 1.0.6 resolves the issue. Hmm...

Doesn't make sense as I was using 1.0.6 for most of the time. Unless the previous firmware release set it on a path to failure and the firmware update can't fix it once the damage is done? 

I'm assuming everyone that went through RMA had to update their switch to 1.0.6, it didn't arrive with this firmware?

  @Utmstgsn I had a total of 3 of these exchanged (all at the same time). The newly received switches have firmware version 1.0.6.

Replying to myself here.

The two EAPs that I thought were faulty were actually OK once I connected them to a network with a DHCP server. I thought that EAP660HDs had a fallback address configured as 192.168.0.1 but I think it's actually at the other end of the subnet at 192.168.0.254. In any case I couldn't get onto the EAP until after I did a factory reset and got a DHCP assignment.

I finally got all my EAPs back in operation which is a great relief. All working through the TL-SG108E (with three SSIDs on three VLANs) and so much faster than our old WiFi setup.

Sadly, though one EAP has failed Adoption in Omada after a (Omada recommended) firmware upgrade. It just keeps failing the adoption with something like 'Failed to respond to adoption commands'... So now I'm back to three EAPs and will be calling support again!

  @yzenezy 

I got my replacement. A few things I noticed, although I don't know if they are things I just didn't notice before:

• The fans now run quieter. Pretty sure they ran almost full-blast.
• The link lights actually flicker now, pretty sure they were just stuck on before they failed entirely.

Anyway, so far so good. It came with 1.0.6 - hopefully that'll be the end of it. 

To TP-Links credit, they processed the RMA quickly and Amazon sent me the replacement before I even had to send the broken one back - so I ended up getting it ahead of schedule. 

  @KrisG Are the new switches still hw version v1 or higher

KrisG wrote

  @Utmstgsn I had a total of 3 of these exchanged (all at the same time). The newly received switches have firmware version 1.0.6.